diff --git a/.gitignore b/.gitignore
index e8af5af..6f5f8d5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,3 +5,4 @@ npm-debug.log
 /.nyc_output
 /coverage
 /esdoc
+/y-leveldb-databases
diff --git a/Dockerfile b/Dockerfile
index e2c9320..0ef4ad7 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -16,4 +16,6 @@ RUN yarn run build
 
 EXPOSE 8080
 
+VOLUME ["/usr/src/app/y-leveldb-databases"]
+
 CMD ["yarn", "run", "server"]
diff --git a/README.md b/README.md
index b1619d4..b51cb65 100644
--- a/README.md
+++ b/README.md
@@ -38,7 +38,7 @@ Now you can visit `http://localhost:8080/` to view the application.
 
 ```bash
 docker build . -t cattaz # --build-arg http_proxy=http://user:pass@proxy.example.com:8080 --build-arg https_proxy=http://user:pass@proxy.example.com:8080
-docker run -it -p 8080:8080 cattaz
+docker run -it -p 8080:8080 -v $(pwd)/y-leveldb-databases:/usr/src/app/y-leveldb-databases cattaz
 ```
 
 Now you can visit `http://localhost:8080/` to view the application.
diff --git a/docker-compose.yml b/docker-compose.yml
index f7f16e9..21f125c 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -9,3 +9,5 @@ services:
         PORT: ${PORT:-8080}
     ports:
       - "${PORT:-8080}:8080"
+    volumes:
+      - ./y-leveldb-databases:/usr/src/app/y-leveldb-databases
diff --git a/docs/ja/usage.cattaz.md b/docs/ja/usage.cattaz.md
index 32b12c7..fe18799 100644
--- a/docs/ja/usage.cattaz.md
+++ b/docs/ja/usage.cattaz.md
@@ -20,7 +20,7 @@ yarn start
 
 ```bash
 docker build . -t cattaz # --build-arg http_proxy=http://user:pass@proxy.example.com:8080 --build-arg https_proxy=http://user:pass@proxy.example.com:8080
-docker run -it -p 8080:8080 cattaz
+docker run -it -p 8080:8080 -v $(pwd)/y-leveldb-databases:/usr/src/app/y-leveldb-databases cattaz
 ```
 
 上記コマンドを実行後、`http://localhost:8080/`にアクセスするとアプリケーションを見ることができます。
diff --git a/docs/usage.cattaz.md b/docs/usage.cattaz.md
index 9f8eacd..f3572d4 100644
--- a/docs/usage.cattaz.md
+++ b/docs/usage.cattaz.md
@@ -20,7 +20,7 @@ Default port is 8080. To change port number, use `PORT=12345 yarn start` instead
 
 ```bash
 docker build . -t cattaz # --build-arg http_proxy=http://user:pass@proxy.example.com:8080 --build-arg https_proxy=http://user:pass@proxy.example.com:8080
-docker run -it -p 8080:8080 cattaz
+docker run -it -p 8080:8080 -v $(pwd)/y-leveldb-databases:/usr/src/app/y-leveldb-databases cattaz
 ```
 
 Now you can visit `http://localhost:8080/` to view the application.
diff --git a/package.json b/package.json
index 0c95f72..bcf6884 100644
--- a/package.json
+++ b/package.json
@@ -14,6 +14,8 @@
     "github-markdown-css": "^2.10.0",
     "hast-to-hyperscript": "^5.0.0",
     "js-yaml": "^3.12.0",
+    "leveldown": "^2.1.1",
+    "levelup": "^2.0.1",
     "lodash": "^4.17.10",
     "mdast-util-to-hast": "^3.0.2",
     "prop-types": "^15.6.2",
@@ -28,10 +30,12 @@
     "react-split-pane": "^0.1.82",
     "react-timeago": "^4.1.9",
     "remark": "^9.0.0",
+    "rimraf": "^2.6.2",
     "socket.io": "1.3.7",
     "socket.io-client": "1.3.7",
     "whatwg-fetch": "^2.0.4",
     "y-array": "^10.1.4",
+    "y-leveldb": "^0.0.3",
     "y-memory": "^8.0.9",
     "y-text": "^9.5.1",
     "y-websockets-client": "^8.0.16",
@@ -73,7 +77,7 @@
     "postcss": "^7.0.2",
     "postcss-loader": "^3.0.0",
     "react-test-renderer": "^16.4.2",
-    "rimraf": "^2.6.2",
+    "sanitize-filename": "^1.6.1",
     "sinon": "^6.1.5",
     "source-map-explorer": "^1.6.0",
     "webpack": "^4.16.5",
diff --git a/server.js b/server.js
index 15502e3..c1f70ed 100644
--- a/server.js
+++ b/server.js
@@ -6,7 +6,7 @@ import 'babel-polyfill';
 
 import Y from 'yjs';
 import yWebsocketsServer from 'y-websockets-server';
-import yMemory from 'y-memory';
+import yleveldb from 'y-leveldb';
 
 import express from 'express';
 import socketIo from 'socket.io';
@@ -15,7 +15,9 @@ import bodyParser from 'body-parser';
 import clone from 'lodash/clone';
 import crypto from 'crypto';
 
-Y.extend(yWebsocketsServer, yMemory);
+import LevelDBLib from './src/server/LevelDBLib';
+
+Y.extend(yWebsocketsServer, yleveldb);
 
 const isProduction = process.env.NODE_ENV === 'production';
 const serverMode = process.env.SERVER_MODE;
@@ -27,15 +29,15 @@ const io = socketIo.listen(server);
 const bodyParserText = bodyParser.text();
 
 const yInstances = {};
-const metadata = {};
+const metadata = LevelDBLib.restoreMetadata('y-leveldb-databases');
 
 function getInstanceOfY(room) {
   if (yInstances[room] == null) {
     yInstances[room] = Y({
       db: {
-        name: 'memory',
+        name: 'leveldb',
         dir: 'y-leveldb-databases',
-        namespace: room,
+        namespace: LevelDBLib.escapeNamespace(room),
       },
       connector: {
         name: 'websockets-server',
@@ -46,18 +48,16 @@ function getInstanceOfY(room) {
       },
       share: {},
     });
-    metadata[room] = {
-      created: new Date(),
-      modified: new Date(),
-      active: 0,
-    };
+    if (!metadata[room]) {
+      metadata[room] = {
+        created: new Date(),
+        modified: new Date(),
+        active: 0,
+      };
+    }
   }
   return yInstances[room];
 }
-function removeInstanceOfY(room) {
-  delete yInstances[room];
-  delete metadata[room];
-}
 
 function getSha1Hash(plaintext) {
   const sha1 = crypto.createHash('sha1');
@@ -83,13 +83,7 @@ app.post('/deletePage', bodyParserText, async (req, res) => {
   res.setHeader('Access-Control-Allow-Origin', '*');
   res.setHeader('Content-Type', 'application/json');
   const room = req.body;
-  const yPromise = yInstances[room];
-  if (!yPromise) {
-    res.end(JSON.stringify({ status: 'FAILURE', msg: 'No y instance' }));
-    return;
-  }
   try {
-    const y = await yPromise;
     const roomMetadata = metadata[room];
     if (!roomMetadata) {
       res.end(JSON.stringify({ status: 'FAILURE', msg: 'No metadata' }));
@@ -99,17 +93,12 @@ app.post('/deletePage', bodyParserText, async (req, res) => {
       res.end(JSON.stringify({ status: 'FAILURE', msg: 'There are still users on this page' }));
       return;
     }
-    try {
-      await y.destroy();
-      removeInstanceOfY(room);
-      res.end(JSON.stringify({ status: 'SUCCESS', msg: `Delete ${room}` }));
-    } catch (ex) {
-      console.error(ex);
-      res.end(JSON.stringify({ status: 'FAILURE', msg: 'Y instance destroy error' }));
-    }
+    await LevelDBLib.deleteDatabase('y-leveldb-databases', room);
+    delete metadata[room];
+    res.end(JSON.stringify({ status: 'SUCCESS', msg: `Delete ${room}` }));
   } catch (ex) {
     console.error(ex);
-    res.end(JSON.stringify({ status: 'FAILURE', msg: ex }));
+    res.end(JSON.stringify({ status: 'FAILURE', msg: 'Failed to delete database' }));
   }
 });
 
@@ -148,6 +137,13 @@ io.on('connection', (socket) => {
       const escapedRoom = encodeURIComponent(room);
       io.in(escapedRoom).emit('activeUser', metadata[room].active);
       io.in(escapedRoom).emit('clientCursor', { type: 'delete', id: getSha1Hash(socket.id) });
+      if (metadata[room].active === 0) {
+        LevelDBLib.closeDatabase(y).then(() => {
+          delete yInstances[room];
+        }, (ex) => {
+          console.error(ex);
+        });
+      }
     }));
     rooms.splice(0, rooms.length);
   });
@@ -162,6 +158,13 @@ io.on('connection', (socket) => {
       metadata[room].active -= 1;
       io.in(room).emit('activeUser', metadata[room].active);
       io.in(room).emit('clientCursor', { type: 'delete', id: getSha1Hash(socket.id) });
+      if (metadata[room].active === 0) {
+        LevelDBLib.closeDatabase(y).then(() => {
+          delete yInstances[room];
+        }, (ex) => {
+          console.error(ex);
+        });
+      }
     }
   });
   socket.on('clientCursor', (msg) => {
diff --git a/src/server/LevelDBLib.js b/src/server/LevelDBLib.js
new file mode 100644
index 0000000..88ed6d0
--- /dev/null
+++ b/src/server/LevelDBLib.js
@@ -0,0 +1,103 @@
+import { join, sep } from 'path';
+import { lstatSync, readdirSync } from 'fs';
+import rimraf from 'rimraf';
+
+const unsafeChars = /[^-_a-zA-Z0-9]/g;
+const windowsReserved = /^(con|prn|aux|nul|com[0-9]|lpt[0-9])(\..*)?$/i;
+const escapeSeq = /%([_0-9a-fA-F]+)%/g;
+
+export default class LevelDBLib {
+  /**
+   * It escapes a namespace to a safe file name.
+   * This function is injective.
+   * @param {string} namespace namespace of Level DB
+   * @returns {string}
+   */
+  static escapeNamespace(namespace) {
+    if (!namespace) return '%_%';
+    if (namespace.match(windowsReserved)) {
+      return `%_%${namespace}`;
+    }
+    return namespace.replace(unsafeChars, substr => `%${substr.charCodeAt(0).toString(16)}%`);
+  }
+
+  /**
+   * Reversed function of escapeNamespace.
+   * @param {string} escapedNamedpace file name generated by escapeNamespace
+   * @returns {string}
+   */
+  static unescapeNamespace(escapedNamedpace) {
+    return escapedNamedpace.replace(escapeSeq, (substr, group) => {
+      if (group === '_') return '';
+      return String.fromCharCode(parseInt(group, 16));
+    });
+  }
+
+  static restoreMetadata(path) {
+    const isDirectory = (source) => {
+      try {
+        return lstatSync(source).isDirectory();
+      } catch (e) {
+        return false;
+      }
+    };
+    const getDirectories = source => (isDirectory(source) ? readdirSync(source).map(name => join(source, name)).filter(isDirectory) : []);
+    const pages = getDirectories(path).map(p => LevelDBLib.unescapeNamespace(p.split(sep)[1]));
+    return pages.reduce((accumulator, p) => {
+      const dbPath = join(path, LevelDBLib.escapeNamespace(p));
+      const directoryCreated = lstatSync(dbPath).ctime; // Not correct on Linux
+      const latestFileModified = new Date(Math.max(...readdirSync(dbPath).map(name => join(dbPath, name)).map(f => lstatSync(f).mtimeMs)));
+      return Object.assign(accumulator, {
+        [p]: {
+          created: directoryCreated,
+          modified: latestFileModified,
+          active: 0,
+        },
+      });
+    }, {});
+  }
+
+  /**
+   * Closes database
+   * @param {*} y y instance
+   * @returns {Promise}
+   */
+  static closeDatabase(y) {
+    // Because y.close waits whenTransactionsFinished forever,
+    // we copied y.close and removed whenTransactionsFinished.
+    if (y.connector.destroy != null) {
+      y.connector.destroy();
+    } else {
+      y.connector.disconnect();
+    }
+    y.connector.disconnect();
+    y.db.destroyTypes();
+    const g = y.db.destroy();
+    for (;;) {
+      const i = g.next();
+      if (i.done) {
+        break;
+      }
+    }
+    return y.db.whenTransactionsFinished();
+  }
+
+  /**
+   * Deletes database. The database must be closed before deleting.
+   * @param {string} path parent directory of each levelDB database
+   * @param {string} page raw page name of wiki page
+   * @returns {Promise}
+   */
+  static deleteDatabase(path, page) {
+    const dbpath = join(path, LevelDBLib.escapeNamespace(page));
+    return new Promise((resolve, reject) => {
+      rimraf(dbpath, {}, (err) => {
+        if (err) {
+          reject(err);
+          return;
+        }
+        resolve();
+      });
+    });
+  }
+}
diff --git a/test/server/LevelDBLib.ava.js b/test/server/LevelDBLib.ava.js
new file mode 100644
index 0000000..c0d94a8
--- /dev/null
+++ b/test/server/LevelDBLib.ava.js
@@ -0,0 +1,93 @@
+import test from 'ava';
+import sanitize from 'sanitize-filename';
+
+import LevelDBLib from '../../src/server/LevelDBLib';
+
+const unsafePaths = [
+  // path traversal
+  '/',
+  '/etc/passwd',
+  '.',
+  './..',
+  './dir/../..',
+  '..',
+  '../',
+  // invalid filename
+  '',
+  ' ',
+  'last space ',
+  'last-dot.',
+  'con',
+  'con.txt',
+  'nul',
+  // illegal chars
+  'question?mark?char',
+  'angle<>char',
+  'asterisk*char',
+  'null\0char',
+  'newline\nchar',
+  'tab\tchar',
+  // path separator
+  'dir/file',
+  'dir\\file',
+];
+
+/** @test {LevelDBLib.escapeNamespace} */
+test('escapeNamespace should escape unsafe path', t => {
+  unsafePaths.forEach(p => {
+    const escaped = LevelDBLib.escapeNamespace(p);
+    t.not(p, escaped, 'should escape unsafe filename');
+    const sanitizedEscaped = sanitize(escaped);
+    t.is(escaped, sanitizedEscaped, 'escaped namespace must be a safe filename');
+  });
+});
+
+/** @test {LevelDBLib.unescapeNamespace} */
+test('unescapeNamespace should unescape path', t => {
+  unsafePaths.forEach(p => {
+    const escaped = LevelDBLib.escapeNamespace(p);
+    const unescaped = LevelDBLib.unescapeNamespace(escaped);
+    t.is(p, unescaped);
+  });
+});
+
+/** @test {LevelDBLib.escapeNamespace} */
+test('escapeNamespace should be injective', t => {
+  const inputs = new Set([
+    '',
+    '%',
+    '%%',
+    '%%%',
+    '%_%',
+    '%%_%',
+    '%%__%',
+    '%1%',
+    '%01%',
+  ]);
+  const outputs = new Set();
+  inputs.forEach(p => {
+    const escaped = LevelDBLib.escapeNamespace(p);
+    t.false(outputs.has(escaped), `not injective: ${p} -> ${escaped}`);
+    outputs.add(escaped);
+  });
+});
+
+/** @test {LevelDBLib.escapeNamespace} */
+test('escapeNamespace should handle non-ascii chars', t => {
+  const inputs = new Set([
+    'ひらがな',
+    'カタカナ',
+    '漢字',
+    '汉语',
+    '한글',
+    'عربی زبان',
+  ]);
+  inputs.forEach(p => {
+    const escaped = LevelDBLib.escapeNamespace(p);
+    t.not(p, escaped, 'should escape');
+    const sanitizedEscaped = sanitize(escaped);
+    t.is(escaped, sanitizedEscaped, 'escaped namespace must be a safe filename');
+    const unescaped = LevelDBLib.unescapeNamespace(escaped);
+    t.is(p, unescaped, 'should restore to non-ascii');
+  });
+});
diff --git a/yarn.lock b/yarn.lock
index 61cde2f..1844723 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -501,6 +501,36 @@ abbrev@1:
   version "1.1.1"
   resolved "https://registry.yarnpkg.com/abbrev/-/abbrev-1.1.1.tgz#f8f2c887ad10bf67f634f005b6987fed3179aac8"
 
+abstract-leveldown@~0.12.1:
+  version "0.12.4"
+  resolved "https://registry.yarnpkg.com/abstract-leveldown/-/abstract-leveldown-0.12.4.tgz#29e18e632e60e4e221d5810247852a63d7b2e410"
+  dependencies:
+    xtend "~3.0.0"
+
+abstract-leveldown@~2.6.0, abstract-leveldown@~2.6.1:
+  version "2.6.3"
+  resolved "https://registry.yarnpkg.com/abstract-leveldown/-/abstract-leveldown-2.6.3.tgz#1c5e8c6a5ef965ae8c35dfb3a8770c476b82c4b8"
+  dependencies:
+    xtend "~4.0.0"
+
+abstract-leveldown@~2.7.0:
+  version "2.7.2"
+  resolved "https://registry.yarnpkg.com/abstract-leveldown/-/abstract-leveldown-2.7.2.tgz#87a44d7ebebc341d59665204834c8b7e0932cc93"
+  dependencies:
+    xtend "~4.0.0"
+
+abstract-leveldown@~3.0.0:
+  version "3.0.0"
+  resolved "https://registry.yarnpkg.com/abstract-leveldown/-/abstract-leveldown-3.0.0.tgz#5cb89f958a44f526779d740d1440e743e0c30a57"
+  dependencies:
+    xtend "~4.0.0"
+
+abstract-leveldown@~4.0.0:
+  version "4.0.3"
+  resolved "https://registry.yarnpkg.com/abstract-leveldown/-/abstract-leveldown-4.0.3.tgz#cb636f4965fbe117f5c8b76a7d51dd42aaed0580"
+  dependencies:
+    xtend "~4.0.0"
+
 accepts@~1.3.5:
   version "1.3.5"
   resolved "https://registry.yarnpkg.com/accepts/-/accepts-1.3.5.tgz#eb777df6011723a3b14e8a72c0805c8e86746bd2"
@@ -2049,6 +2079,23 @@ bindings@1.2.x, bindings@~1.2.1:
   version "1.2.1"
   resolved "https://registry.yarnpkg.com/bindings/-/bindings-1.2.1.tgz#14ad6113812d2d37d72e67b4cacb4bb726505f11"
 
+bindings@~1.3.0:
+  version "1.3.0"
+  resolved "https://registry.yarnpkg.com/bindings/-/bindings-1.3.0.tgz#b346f6ecf6a95f5a815c5839fc7cdb22502f1ed7"
+
+bl@^1.0.0:
+  version "1.2.2"
+  resolved "https://registry.yarnpkg.com/bl/-/bl-1.2.2.tgz#a160911717103c07410cef63ef51b397c025af9c"
+  dependencies:
+    readable-stream "^2.3.5"
+    safe-buffer "^5.1.1"
+
+bl@~0.8.1:
+  version "0.8.2"
+  resolved "https://registry.yarnpkg.com/bl/-/bl-0.8.2.tgz#c9b6bca08d1bc2ea00fc8afb4f1a5fd1e1c66e4e"
+  dependencies:
+    readable-stream "~1.0.26"
+
 blob@0.0.4:
   version "0.0.4"
   resolved "https://registry.yarnpkg.com/blob/-/blob-0.0.4.tgz#bcf13052ca54463f30f9fc7e95b9a47630a94921"
@@ -2237,6 +2284,21 @@ buf-compare@^1.0.0:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/buf-compare/-/buf-compare-1.0.1.tgz#fef28da8b8113a0a0db4430b0b6467b69730b34a"
 
+buffer-alloc-unsafe@^1.1.0:
+  version "1.1.0"
+  resolved "https://registry.yarnpkg.com/buffer-alloc-unsafe/-/buffer-alloc-unsafe-1.1.0.tgz#bd7dc26ae2972d0eda253be061dba992349c19f0"
+
+buffer-alloc@^1.1.0:
+  version "1.2.0"
+  resolved "https://registry.yarnpkg.com/buffer-alloc/-/buffer-alloc-1.2.0.tgz#890dd90d923a873e08e10e5fd51a57e5b7cce0ec"
+  dependencies:
+    buffer-alloc-unsafe "^1.1.0"
+    buffer-fill "^1.0.0"
+
+buffer-fill@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/buffer-fill/-/buffer-fill-1.0.0.tgz#f8f78b76789888ef39f205cd637f68e702122b2c"
+
 buffer-from@^1.0.0:
   version "1.1.1"
   resolved "https://registry.yarnpkg.com/buffer-from/-/buffer-from-1.1.1.tgz#32713bc028f75c02fdb710d7c7bcec1f2c6070ef"
@@ -2272,6 +2334,19 @@ bytes@3.0.0:
   version "3.0.0"
   resolved "https://registry.yarnpkg.com/bytes/-/bytes-3.0.0.tgz#d32815404d689699f85a4ea4fa8755dd13a96048"
 
+bytewise-core@^1.2.2:
+  version "1.2.3"
+  resolved "https://registry.yarnpkg.com/bytewise-core/-/bytewise-core-1.2.3.tgz#3fb410c7e91558eb1ab22a82834577aa6bd61d42"
+  dependencies:
+    typewise-core "^1.2"
+
+bytewise@~1.1.0:
+  version "1.1.0"
+  resolved "https://registry.yarnpkg.com/bytewise/-/bytewise-1.1.0.tgz#1d13cbff717ae7158094aa881b35d081b387253e"
+  dependencies:
+    bytewise-core "^1.2.2"
+    typewise "^1.0.3"
+
 cacache@^10.0.4:
   version "10.0.4"
   resolved "https://registry.yarnpkg.com/cacache/-/cacache-10.0.4.tgz#6452367999eff9d4188aefd9a14e9d7c6a263460"
@@ -3298,6 +3373,12 @@ decode-uri-component@^0.2.0:
   version "0.2.0"
   resolved "https://registry.yarnpkg.com/decode-uri-component/-/decode-uri-component-0.2.0.tgz#eb3913333458775cb84cd1a1fae062106bb87545"
 
+decompress-response@^3.3.0:
+  version "3.3.0"
+  resolved "https://registry.yarnpkg.com/decompress-response/-/decompress-response-3.3.0.tgz#80a4dd323748384bfa248083622aedec982adff3"
+  dependencies:
+    mimic-response "^1.0.0"
+
 deep-equal@^1.0.0, deep-equal@^1.0.1:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/deep-equal/-/deep-equal-1.0.1.tgz#f5d260292b660e084eff4cdbc9f08ad3247448b5"
@@ -3326,6 +3407,24 @@ default-require-extensions@^1.0.0:
   dependencies:
     strip-bom "^2.0.0"
 
+deferred-leveldown@~0.2.0:
+  version "0.2.0"
+  resolved "https://registry.yarnpkg.com/deferred-leveldown/-/deferred-leveldown-0.2.0.tgz#2cef1f111e1c57870d8bbb8af2650e587cd2f5b4"
+  dependencies:
+    abstract-leveldown "~0.12.1"
+
+deferred-leveldown@~1.2.1:
+  version "1.2.2"
+  resolved "https://registry.yarnpkg.com/deferred-leveldown/-/deferred-leveldown-1.2.2.tgz#3acd2e0b75d1669924bc0a4b642851131173e1eb"
+  dependencies:
+    abstract-leveldown "~2.6.0"
+
+deferred-leveldown@~3.0.0:
+  version "3.0.0"
+  resolved "https://registry.yarnpkg.com/deferred-leveldown/-/deferred-leveldown-3.0.0.tgz#bff7241bf156aa3635f520bedf34330c408d3307"
+  dependencies:
+    abstract-leveldown "~4.0.0"
+
 define-properties@^1.1.2:
   version "1.1.2"
   resolved "https://registry.yarnpkg.com/define-properties/-/define-properties-1.1.2.tgz#83a73f2fea569898fb737193c8f873caf6d45c94"
@@ -3419,7 +3518,7 @@ detect-indent@^5.0.0:
   version "5.0.0"
   resolved "https://registry.yarnpkg.com/detect-indent/-/detect-indent-5.0.0.tgz#3871cc0a6a002e8c3e5b3cf7f336264675f06b9d"
 
-detect-libc@^1.0.2:
+detect-libc@^1.0.2, detect-libc@^1.0.3:
   version "1.0.3"
   resolved "https://registry.yarnpkg.com/detect-libc/-/detect-libc-1.0.3.tgz#fa137c4bd698edf55cd5cd02ac559f91a4c4ba9b"
 
@@ -3755,7 +3854,7 @@ equal-length@^1.0.0:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/equal-length/-/equal-length-1.0.1.tgz#21ca112d48ab24b4e1e7ffc0e5339d31fdfc274c"
 
-errno@^0.1.3, errno@~0.1.7:
+errno@^0.1.3, errno@~0.1.1, errno@~0.1.7:
   version "0.1.7"
   resolved "https://registry.yarnpkg.com/errno/-/errno-0.1.7.tgz#4684d71779ad39af177e3f007996f7c67c852618"
   dependencies:
@@ -4275,6 +4374,10 @@ expand-range@^1.8.1:
   dependencies:
     fill-range "^2.1.0"
 
+expand-template@^1.0.2:
+  version "1.1.1"
+  resolved "https://registry.yarnpkg.com/expand-template/-/expand-template-1.1.1.tgz#981f188c0c3a87d2e28f559bc541426ff94f21dd"
+
 expand-tilde@^2.0.0, expand-tilde@^2.0.2:
   version "2.0.2"
   resolved "https://registry.yarnpkg.com/expand-tilde/-/expand-tilde-2.0.2.tgz#97e801aa052df02454de46b02bf621642cdc8502"
@@ -4388,6 +4491,10 @@ fast-diff@^1.1.1:
   version "1.1.2"
   resolved "https://registry.yarnpkg.com/fast-diff/-/fast-diff-1.1.2.tgz#4b62c42b8e03de3f848460b639079920695d0154"
 
+fast-future@~1.0.2:
+  version "1.0.2"
+  resolved "https://registry.yarnpkg.com/fast-future/-/fast-future-1.0.2.tgz#8435a9aaa02d79248d17d704e76259301d99280a"
+
 fast-json-stable-stringify@^2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/fast-json-stable-stringify/-/fast-json-stable-stringify-2.0.0.tgz#d5142c0caee6b1189f87d3a76111064f86c8bbf2"
@@ -4606,6 +4713,10 @@ from@~0:
   version "0.1.7"
   resolved "https://registry.yarnpkg.com/from/-/from-0.1.7.tgz#83c60afc58b9c56997007ed1a768b3ab303a44fe"
 
+fs-constants@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/fs-constants/-/fs-constants-1.0.0.tgz#6be0de9be998ce16af8afc24497b9ee9b7ccd9ad"
+
 fs-extra@1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/fs-extra/-/fs-extra-1.0.0.tgz#cd3ce5f7e7cb6145883fcae3191e9877f8587950"
@@ -4729,6 +4840,10 @@ getpass@^0.1.1:
   dependencies:
     assert-plus "^1.0.0"
 
+github-from-package@0.0.0:
+  version "0.0.0"
+  resolved "https://registry.yarnpkg.com/github-from-package/-/github-from-package-0.0.0.tgz#97fb5d96bfde8973313f20e8288ef9a167fa64ce"
+
 github-markdown-css@^2.10.0:
   version "2.10.0"
   resolved "https://registry.yarnpkg.com/github-markdown-css/-/github-markdown-css-2.10.0.tgz#0612fed22816b33b282f37ef8def7a4ecabfe993"
@@ -6144,6 +6259,134 @@ lcov-parse@0.0.10, lcov-parse@^0.0.10:
   version "0.0.10"
   resolved "https://registry.yarnpkg.com/lcov-parse/-/lcov-parse-0.0.10.tgz#1b0b8ff9ac9c7889250582b70b71315d9da6d9a3"
 
+level-codec@~7.0.0:
+  version "7.0.1"
+  resolved "https://registry.yarnpkg.com/level-codec/-/level-codec-7.0.1.tgz#341f22f907ce0f16763f24bddd681e395a0fb8a7"
+
+level-errors@^1.0.3, level-errors@~1.1.0:
+  version "1.1.2"
+  resolved "https://registry.yarnpkg.com/level-errors/-/level-errors-1.1.2.tgz#4399c2f3d3ab87d0625f7e3676e2d807deff404d"
+  dependencies:
+    errno "~0.1.1"
+
+level-errors@~1.0.3:
+  version "1.0.5"
+  resolved "https://registry.yarnpkg.com/level-errors/-/level-errors-1.0.5.tgz#83dbfb12f0b8a2516bdc9a31c4876038e227b859"
+  dependencies:
+    errno "~0.1.1"
+
+level-iterator-stream@~1.3.0:
+  version "1.3.1"
+  resolved "https://registry.yarnpkg.com/level-iterator-stream/-/level-iterator-stream-1.3.1.tgz#e43b78b1a8143e6fa97a4f485eb8ea530352f2ed"
+  dependencies:
+    inherits "^2.0.1"
+    level-errors "^1.0.3"
+    readable-stream "^1.0.33"
+    xtend "^4.0.0"
+
+level-iterator-stream@~2.0.0:
+  version "2.0.3"
+  resolved "https://registry.yarnpkg.com/level-iterator-stream/-/level-iterator-stream-2.0.3.tgz#ccfff7c046dcf47955ae9a86f46dfa06a31688b4"
+  dependencies:
+    inherits "^2.0.1"
+    readable-stream "^2.0.5"
+    xtend "^4.0.0"
+
+level-packager@~1.2.0:
+  version "1.2.1"
+  resolved "https://registry.yarnpkg.com/level-packager/-/level-packager-1.2.1.tgz#067fedfd072b7fe3c6bec6080c0cbd4a6b2e11f4"
+  dependencies:
+    levelup "~1.3.0"
+
+level-post@^1.0.7:
+  version "1.0.7"
+  resolved "https://registry.yarnpkg.com/level-post/-/level-post-1.0.7.tgz#19ccca9441a7cc527879a0635000f06d5e8f27d0"
+  dependencies:
+    ltgt "^2.1.2"
+
+level-sublevel@^6.5.4:
+  version "6.6.5"
+  resolved "https://registry.yarnpkg.com/level-sublevel/-/level-sublevel-6.6.5.tgz#acddfa2be033b9e503544e2c647f3c03d5a23fbd"
+  dependencies:
+    bytewise "~1.1.0"
+    levelup "~0.19.0"
+    ltgt "~2.1.1"
+    pull-defer "^0.2.2"
+    pull-level "^2.0.3"
+    pull-stream "^3.6.8"
+    typewiselite "~1.0.0"
+    xtend "~4.0.0"
+
+level@^1.4.0:
+  version "1.7.0"
+  resolved "https://registry.yarnpkg.com/level/-/level-1.7.0.tgz#43464a3a8ba73b2f3de56a24292805146da213a1"
+  dependencies:
+    level-packager "~1.2.0"
+    leveldown "~1.7.0"
+
+leveldown@^1.7.0-0:
+  version "1.9.0"
+  resolved "https://registry.yarnpkg.com/leveldown/-/leveldown-1.9.0.tgz#057b4b5d9d9717f81fe88c6e6cf962f4b44961a1"
+  dependencies:
+    abstract-leveldown "~2.7.0"
+    bindings "~1.3.0"
+    fast-future "~1.0.2"
+    nan "~2.7.0"
+    prebuild-install "^2.1.0"
+
+leveldown@^2.1.1:
+  version "2.1.1"
+  resolved "https://registry.yarnpkg.com/leveldown/-/leveldown-2.1.1.tgz#2f4d786dfe6ba3ecc63409784ce29eca110413bf"
+  dependencies:
+    abstract-leveldown "~3.0.0"
+    bindings "~1.3.0"
+    fast-future "~1.0.2"
+    nan "~2.8.0"
+    prebuild-install "^2.1.0"
+
+leveldown@~1.7.0:
+  version "1.7.2"
+  resolved "https://registry.yarnpkg.com/leveldown/-/leveldown-1.7.2.tgz#5e3467bb27ee246a4a7b8dbd8fb2b16206a6eb8b"
+  dependencies:
+    abstract-leveldown "~2.6.1"
+    bindings "~1.2.1"
+    fast-future "~1.0.2"
+    nan "~2.6.1"
+    prebuild-install "^2.1.0"
+
+levelup@^1.0.0-4, levelup@~1.3.0:
+  version "1.3.9"
+  resolved "https://registry.yarnpkg.com/levelup/-/levelup-1.3.9.tgz#2dbcae845b2bb2b6bea84df334c475533bbd82ab"
+  dependencies:
+    deferred-leveldown "~1.2.1"
+    level-codec "~7.0.0"
+    level-errors "~1.0.3"
+    level-iterator-stream "~1.3.0"
+    prr "~1.0.1"
+    semver "~5.4.1"
+    xtend "~4.0.0"
+
+levelup@^2.0.1:
+  version "2.0.2"
+  resolved "https://registry.yarnpkg.com/levelup/-/levelup-2.0.2.tgz#83dd22ffd5ee14482143c37cddfb8457854d3727"
+  dependencies:
+    deferred-leveldown "~3.0.0"
+    level-errors "~1.1.0"
+    level-iterator-stream "~2.0.0"
+    xtend "~4.0.0"
+
+levelup@~0.19.0:
+  version "0.19.1"
+  resolved "https://registry.yarnpkg.com/levelup/-/levelup-0.19.1.tgz#f3a6a7205272c4b5f35e412ff004a03a0aedf50b"
+  dependencies:
+    bl "~0.8.1"
+    deferred-leveldown "~0.2.0"
+    errno "~0.1.1"
+    prr "~0.0.0"
+    readable-stream "~1.0.26"
+    semver "~5.1.0"
+    xtend "~3.0.0"
+
 levn@^0.3.0, levn@~0.3.0:
   version "0.3.0"
   resolved "https://registry.yarnpkg.com/levn/-/levn-0.3.0.tgz#3b09924edf9f083c0490fdd4c0bc4421e04764ee"
@@ -6396,6 +6639,14 @@ longest@^1.0.1:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/longest/-/longest-1.0.1.tgz#30a0b2da38f73770e8294a0d22e6625ed77d0097"
 
+looper@^2.0.0:
+  version "2.0.0"
+  resolved "https://registry.yarnpkg.com/looper/-/looper-2.0.0.tgz#66cd0c774af3d4fedac53794f742db56da8f09ec"
+
+looper@^3.0.0:
+  version "3.0.0"
+  resolved "https://registry.yarnpkg.com/looper/-/looper-3.0.0.tgz#2efa54c3b1cbaba9b94aee2e5914b0be57fbb749"
+
 loose-envify@^1.0.0, loose-envify@^1.1.0, loose-envify@^1.2.0, loose-envify@^1.3.1:
   version "1.4.0"
   resolved "https://registry.yarnpkg.com/loose-envify/-/loose-envify-1.4.0.tgz#71ee51fa7be4caec1a63839f7e682d8132d30caf"
@@ -6424,6 +6675,14 @@ lru-cache@^4.0.1, lru-cache@^4.1.1:
     pseudomap "^1.0.2"
     yallist "^2.1.2"
 
+ltgt@^2.1.2:
+  version "2.2.1"
+  resolved "https://registry.yarnpkg.com/ltgt/-/ltgt-2.2.1.tgz#f35ca91c493f7b73da0e07495304f17b31f87ee5"
+
+ltgt@~2.1.1:
+  version "2.1.3"
+  resolved "https://registry.yarnpkg.com/ltgt/-/ltgt-2.1.3.tgz#10851a06d9964b971178441c23c9e52698eece34"
+
 make-dir@^1.0.0:
   version "1.3.0"
   resolved "https://registry.yarnpkg.com/make-dir/-/make-dir-1.3.0.tgz#79c1033b80515bd6d24ec9933e860ca75ee27f0c"
@@ -6694,6 +6953,10 @@ mimic-fn@^1.0.0:
   version "1.2.0"
   resolved "https://registry.yarnpkg.com/mimic-fn/-/mimic-fn-1.2.0.tgz#820c86a39334640e99516928bd03fca88057d022"
 
+mimic-response@^1.0.0:
+  version "1.0.1"
+  resolved "https://registry.yarnpkg.com/mimic-response/-/mimic-response-1.0.1.tgz#4923538878eef42063cb8a3e3b0798781487ab1b"
+
 min-document@^2.19.0:
   version "2.19.0"
   resolved "https://registry.yarnpkg.com/min-document/-/min-document-2.19.0.tgz#7bd282e3f5842ed295bb748cdd9f1ffa2c824685"
@@ -6821,6 +7084,18 @@ nan@~2.4.0:
   version "2.4.0"
   resolved "https://registry.yarnpkg.com/nan/-/nan-2.4.0.tgz#fb3c59d45fe4effe215f0b890f8adf6eb32d2232"
 
+nan@~2.6.1:
+  version "2.6.2"
+  resolved "https://registry.yarnpkg.com/nan/-/nan-2.6.2.tgz#e4ff34e6c95fdfb5aecc08de6596f43605a7db45"
+
+nan@~2.7.0:
+  version "2.7.0"
+  resolved "https://registry.yarnpkg.com/nan/-/nan-2.7.0.tgz#d95bf721ec877e08db276ed3fc6eb78f9083ad46"
+
+nan@~2.8.0:
+  version "2.8.0"
+  resolved "https://registry.yarnpkg.com/nan/-/nan-2.8.0.tgz#ed715f3fe9de02b57a5e6252d90a96675e1f085a"
+
 nanomatch@^1.2.9:
   version "1.2.13"
   resolved "https://registry.yarnpkg.com/nanomatch/-/nanomatch-1.2.13.tgz#b87a8aa4fc0de8fe6be88895b38983ff265bd119"
@@ -6891,6 +7166,12 @@ no-case@^2.2.0:
   dependencies:
     lower-case "^1.1.1"
 
+node-abi@^2.2.0:
+  version "2.4.3"
+  resolved "https://registry.yarnpkg.com/node-abi/-/node-abi-2.4.3.tgz#43666b7b17e57863e572409edbb82115ac7af28b"
+  dependencies:
+    semver "^5.4.1"
+
 node-dir@^0.1.10:
   version "0.1.17"
   resolved "https://registry.yarnpkg.com/node-dir/-/node-dir-0.1.17.tgz#5f5665d93351335caabef8f1c554516cf5f1e4e5"
@@ -6954,6 +7235,10 @@ nomnom@~1.6.2:
     colors "0.5.x"
     underscore "~1.4.4"
 
+noop-logger@^0.1.1:
+  version "0.1.1"
+  resolved "https://registry.yarnpkg.com/noop-logger/-/noop-logger-0.1.1.tgz#94a2b1633c4f1317553007d8966fd0e841b6a4c2"
+
 nopt@^4.0.1:
   version "4.0.1"
   resolved "https://registry.yarnpkg.com/nopt/-/nopt-4.0.1.tgz#d0d4685afd5415193c8c7505602d0d17cd64474d"
@@ -7020,7 +7305,7 @@ npm-run-path@^2.0.0:
   dependencies:
     path-key "^2.0.0"
 
-npmlog@^4.0.2, npmlog@^4.1.2:
+npmlog@^4.0.1, npmlog@^4.0.2, npmlog@^4.1.2:
   version "4.1.2"
   resolved "https://registry.yarnpkg.com/npmlog/-/npmlog-4.1.2.tgz#08a7f2a8bf734604779a9efa4ad5cc717abb954b"
   dependencies:
@@ -7899,6 +8184,26 @@ postcss@^7.0.0, postcss@^7.0.2:
     source-map "^0.6.1"
     supports-color "^5.4.0"
 
+prebuild-install@^2.1.0:
+  version "2.5.3"
+  resolved "https://registry.yarnpkg.com/prebuild-install/-/prebuild-install-2.5.3.tgz#9f65f242782d370296353710e9bc843490c19f69"
+  dependencies:
+    detect-libc "^1.0.3"
+    expand-template "^1.0.2"
+    github-from-package "0.0.0"
+    minimist "^1.2.0"
+    mkdirp "^0.5.1"
+    node-abi "^2.2.0"
+    noop-logger "^0.1.1"
+    npmlog "^4.0.1"
+    os-homedir "^1.0.1"
+    pump "^2.0.1"
+    rc "^1.1.6"
+    simple-get "^2.7.0"
+    tar-fs "^1.13.0"
+    tunnel-agent "^0.6.0"
+    which-pm-runs "^1.0.0"
+
 prelude-ls@~1.1.2:
   version "1.1.2"
   resolved "https://registry.yarnpkg.com/prelude-ls/-/prelude-ls-1.1.2.tgz#21932a549f5e52ffd9a827f570e04be62a97da54"
@@ -7988,6 +8293,10 @@ proxy-addr@~2.0.3:
     forwarded "~0.1.2"
     ipaddr.js "1.8.0"
 
+prr@~0.0.0:
+  version "0.0.0"
+  resolved "https://registry.yarnpkg.com/prr/-/prr-0.0.0.tgz#1a84b85908325501411853d0081ee3fa86e2926a"
+
 prr@~1.0.1:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/prr/-/prr-1.0.1.tgz#d3fc114ba06995a45ec6893f484ceb1d78f5f476"
@@ -8016,6 +8325,54 @@ public-encrypt@^4.0.0:
     parse-asn1 "^5.0.0"
     randombytes "^2.0.1"
 
+pull-cat@^1.1.9:
+  version "1.1.11"
+  resolved "https://registry.yarnpkg.com/pull-cat/-/pull-cat-1.1.11.tgz#b642dd1255da376a706b6db4fa962f5fdb74c31b"
+
+pull-defer@^0.2.2:
+  version "0.2.3"
+  resolved "https://registry.yarnpkg.com/pull-defer/-/pull-defer-0.2.3.tgz#4ee09c6d9e227bede9938db80391c3dac489d113"
+
+pull-level@^2.0.3:
+  version "2.0.4"
+  resolved "https://registry.yarnpkg.com/pull-level/-/pull-level-2.0.4.tgz#4822e61757c10bdcc7cf4a03af04c92734c9afac"
+  dependencies:
+    level-post "^1.0.7"
+    pull-cat "^1.1.9"
+    pull-live "^1.0.1"
+    pull-pushable "^2.0.0"
+    pull-stream "^3.4.0"
+    pull-window "^2.1.4"
+    stream-to-pull-stream "^1.7.1"
+
+pull-live@^1.0.1:
+  version "1.0.1"
+  resolved "https://registry.yarnpkg.com/pull-live/-/pull-live-1.0.1.tgz#a4ecee01e330155e9124bbbcf4761f21b38f51f5"
+  dependencies:
+    pull-cat "^1.1.9"
+    pull-stream "^3.4.0"
+
+pull-pushable@^2.0.0:
+  version "2.2.0"
+  resolved "https://registry.yarnpkg.com/pull-pushable/-/pull-pushable-2.2.0.tgz#5f2f3aed47ad86919f01b12a2e99d6f1bd776581"
+
+pull-stream@^3.2.3, pull-stream@^3.4.0, pull-stream@^3.6.8:
+  version "3.6.8"
+  resolved "https://registry.yarnpkg.com/pull-stream/-/pull-stream-3.6.8.tgz#d63dee1c55ff2023fd380f724c387e931b752413"
+
+pull-window@^2.1.4:
+  version "2.1.4"
+  resolved "https://registry.yarnpkg.com/pull-window/-/pull-window-2.1.4.tgz#fc3b86feebd1920c7ae297691e23f705f88552f0"
+  dependencies:
+    looper "^2.0.0"
+
+pump@^1.0.0:
+  version "1.0.3"
+  resolved "https://registry.yarnpkg.com/pump/-/pump-1.0.3.tgz#5dfe8311c33bbf6fc18261f9f34702c47c08a954"
+  dependencies:
+    end-of-stream "^1.1.0"
+    once "^1.3.1"
+
 pump@^2.0.0, pump@^2.0.1:
   version "2.0.1"
   resolved "https://registry.yarnpkg.com/pump/-/pump-2.0.1.tgz#12399add6e4cf7526d973cbc8b5ce2e2908b3909"
@@ -8415,7 +8772,7 @@ read-pkg@^3.0.0:
     normalize-package-data "^2.3.2"
     path-type "^3.0.0"
 
-"readable-stream@1 || 2", readable-stream@^2.0.0, readable-stream@^2.0.1, readable-stream@^2.0.2, readable-stream@^2.0.4, readable-stream@^2.0.6, readable-stream@^2.1.5, readable-stream@^2.2.2, readable-stream@^2.3.3, readable-stream@^2.3.6:
+"readable-stream@1 || 2", readable-stream@^2.0.0, readable-stream@^2.0.1, readable-stream@^2.0.2, readable-stream@^2.0.4, readable-stream@^2.0.5, readable-stream@^2.0.6, readable-stream@^2.1.5, readable-stream@^2.2.2, readable-stream@^2.3.0, readable-stream@^2.3.3, readable-stream@^2.3.5, readable-stream@^2.3.6:
   version "2.3.6"
   resolved "https://registry.yarnpkg.com/readable-stream/-/readable-stream-2.3.6.tgz#b11c27d88b8ff1fbe070643cf94b0c79ae1b0aaf"
   dependencies:
@@ -8427,7 +8784,7 @@ read-pkg@^3.0.0:
     string_decoder "~1.1.1"
     util-deprecate "~1.0.1"
 
-readable-stream@1.0:
+readable-stream@1.0, readable-stream@~1.0.26:
   version "1.0.34"
   resolved "https://registry.yarnpkg.com/readable-stream/-/readable-stream-1.0.34.tgz#125820e34bc842d2f2aaafafe4c2916ee32c157c"
   dependencies:
@@ -8445,6 +8802,15 @@ readable-stream@1.1:
     isarray "0.0.1"
     string_decoder "~0.10.x"
 
+readable-stream@^1.0.33:
+  version "1.1.14"
+  resolved "https://registry.yarnpkg.com/readable-stream/-/readable-stream-1.1.14.tgz#7cf4c54ef648e3813084c636dd2079e166c081d9"
+  dependencies:
+    core-util-is "~1.0.0"
+    inherits "~2.0.1"
+    isarray "0.0.1"
+    string_decoder "~0.10.x"
+
 readdirp@^2.0.0:
   version "2.1.0"
   resolved "https://registry.yarnpkg.com/readdirp/-/readdirp-2.1.0.tgz#4ed0ad060df3073300c48440373f72d1cc642d78"
@@ -8922,6 +9288,12 @@ samsam@1.3.0:
   version "1.3.0"
   resolved "https://registry.yarnpkg.com/samsam/-/samsam-1.3.0.tgz#8d1d9350e25622da30de3e44ba692b5221ab7c50"
 
+sanitize-filename@^1.6.1:
+  version "1.6.1"
+  resolved "https://registry.yarnpkg.com/sanitize-filename/-/sanitize-filename-1.6.1.tgz#612da1c96473fa02dccda92dcd5b4ab164a6772a"
+  dependencies:
+    truncate-utf8-bytes "^1.0.0"
+
 sax@^1.1.4, sax@^1.2.4, sax@~1.2.1:
   version "1.2.4"
   resolved "https://registry.yarnpkg.com/sax/-/sax-1.2.4.tgz#2816234e2378bddc4e5354fab5caa895df7100d9"
@@ -8957,6 +9329,14 @@ semver-diff@^2.0.0:
   version "5.5.0"
   resolved "https://registry.yarnpkg.com/semver/-/semver-5.5.0.tgz#dc4bbc7a6ca9d916dee5d43516f0092b58f7b8ab"
 
+semver@~5.1.0:
+  version "5.1.1"
+  resolved "https://registry.yarnpkg.com/semver/-/semver-5.1.1.tgz#a3292a373e6f3e0798da0b20641b9a9c5bc47e19"
+
+semver@~5.4.1:
+  version "5.4.1"
+  resolved "https://registry.yarnpkg.com/semver/-/semver-5.4.1.tgz#e059c09d8571f0540823733433505d3a2f00b18e"
+
 send@0.16.2:
   version "0.16.2"
   resolved "https://registry.yarnpkg.com/send/-/send-0.16.2.tgz#6ecca1e0f8c156d141597559848df64730a6bbc1"
@@ -9088,6 +9468,18 @@ signal-exit@^3.0.0, signal-exit@^3.0.1, signal-exit@^3.0.2:
   version "3.0.2"
   resolved "https://registry.yarnpkg.com/signal-exit/-/signal-exit-3.0.2.tgz#b5fdc08f1287ea1178628e415e25132b73646c6d"
 
+simple-concat@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/simple-concat/-/simple-concat-1.0.0.tgz#7344cbb8b6e26fb27d66b2fc86f9f6d5997521c6"
+
+simple-get@^2.7.0:
+  version "2.8.1"
+  resolved "https://registry.yarnpkg.com/simple-get/-/simple-get-2.8.1.tgz#0e22e91d4575d87620620bc91308d57a77f44b5d"
+  dependencies:
+    decompress-response "^3.3.0"
+    once "^1.3.1"
+    simple-concat "^1.0.0"
+
 sinon@^6.1.5:
   version "6.1.5"
   resolved "https://registry.yarnpkg.com/sinon/-/sinon-6.1.5.tgz#41451502d43cd5ffb9d051fbf507952400e81d09"
@@ -9424,6 +9816,13 @@ stream-shift@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/stream-shift/-/stream-shift-1.0.0.tgz#d5c752825e5367e786f78e18e445ea223a155952"
 
+stream-to-pull-stream@^1.7.1:
+  version "1.7.2"
+  resolved "https://registry.yarnpkg.com/stream-to-pull-stream/-/stream-to-pull-stream-1.7.2.tgz#757609ae1cebd33c7432d4afbe31ff78650b9dde"
+  dependencies:
+    looper "^3.0.0"
+    pull-stream "^3.2.3"
+
 strict-uri-encode@^1.0.0:
   version "1.1.0"
   resolved "https://registry.yarnpkg.com/strict-uri-encode/-/strict-uri-encode-1.1.0.tgz#279b225df1d582b1f54e65addd4352e18faa0713"
@@ -9658,6 +10057,27 @@ tapable@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/tapable/-/tapable-1.0.0.tgz#cbb639d9002eed9c6b5975eb20598d7936f1f9f2"
 
+tar-fs@^1.13.0:
+  version "1.16.3"
+  resolved "https://registry.yarnpkg.com/tar-fs/-/tar-fs-1.16.3.tgz#966a628841da2c4010406a82167cbd5e0c72d509"
+  dependencies:
+    chownr "^1.0.1"
+    mkdirp "^0.5.1"
+    pump "^1.0.0"
+    tar-stream "^1.1.2"
+
+tar-stream@^1.1.2:
+  version "1.6.1"
+  resolved "https://registry.yarnpkg.com/tar-stream/-/tar-stream-1.6.1.tgz#f84ef1696269d6223ca48f6e1eeede3f7e81f395"
+  dependencies:
+    bl "^1.0.0"
+    buffer-alloc "^1.1.0"
+    end-of-stream "^1.0.0"
+    fs-constants "^1.0.0"
+    readable-stream "^2.3.0"
+    to-buffer "^1.1.0"
+    xtend "^4.0.0"
+
 tar@^4:
   version "4.4.6"
   resolved "https://registry.yarnpkg.com/tar/-/tar-4.4.6.tgz#63110f09c00b4e60ac8bcfe1bf3c8660235fbc9b"
@@ -9744,6 +10164,10 @@ to-arraybuffer@^1.0.0:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/to-arraybuffer/-/to-arraybuffer-1.0.1.tgz#7d229b1fcc637e466ca081180836a7aabff83f43"
 
+to-buffer@^1.1.0:
+  version "1.1.1"
+  resolved "https://registry.yarnpkg.com/to-buffer/-/to-buffer-1.1.1.tgz#493bd48f62d7c43fcded313a03dcadb2e1213a80"
+
 to-fast-properties@^1.0.3:
   version "1.0.3"
   resolved "https://registry.yarnpkg.com/to-fast-properties/-/to-fast-properties-1.0.3.tgz#b83571fa4d8c25b82e231b06e3a3055de4ca1a47"
@@ -9823,6 +10247,12 @@ trough@^1.0.0:
   version "1.0.3"
   resolved "https://registry.yarnpkg.com/trough/-/trough-1.0.3.tgz#e29bd1614c6458d44869fc28b255ab7857ef7c24"
 
+truncate-utf8-bytes@^1.0.0:
+  version "1.0.2"
+  resolved "https://registry.yarnpkg.com/truncate-utf8-bytes/-/truncate-utf8-bytes-1.0.2.tgz#405923909592d56f78a5818434b0b78489ca5f2b"
+  dependencies:
+    utf8-byte-length "^1.0.1"
+
 tslib@^1.9.0:
   version "1.9.3"
   resolved "https://registry.yarnpkg.com/tslib/-/tslib-1.9.3.tgz#d7e4dd79245d85428c4d7e4822a79917954ca286"
@@ -9866,6 +10296,20 @@ typedarray@^0.0.6:
   version "0.0.6"
   resolved "https://registry.yarnpkg.com/typedarray/-/typedarray-0.0.6.tgz#867ac74e3864187b1d3d47d996a78ec5c8830777"
 
+typewise-core@^1.2, typewise-core@^1.2.0:
+  version "1.2.0"
+  resolved "https://registry.yarnpkg.com/typewise-core/-/typewise-core-1.2.0.tgz#97eb91805c7f55d2f941748fa50d315d991ef195"
+
+typewise@^1.0.3:
+  version "1.0.3"
+  resolved "https://registry.yarnpkg.com/typewise/-/typewise-1.0.3.tgz#1067936540af97937cc5dcf9922486e9fa284651"
+  dependencies:
+    typewise-core "^1.2.0"
+
+typewiselite@~1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/typewiselite/-/typewiselite-1.0.0.tgz#c8882fa1bb1092c06005a97f34ef5c8508e3664e"
+
 ua-parser-js@^0.7.18:
   version "0.7.18"
   resolved "https://registry.yarnpkg.com/ua-parser-js/-/ua-parser-js-0.7.18.tgz#a7bfd92f56edfb117083b69e31d2aa8882d4b1ed"
@@ -10148,6 +10592,10 @@ utf-8-validate@1.2.x:
     bindings "~1.2.1"
     nan "~2.4.0"
 
+utf8-byte-length@^1.0.1:
+  version "1.0.4"
+  resolved "https://registry.yarnpkg.com/utf8-byte-length/-/utf8-byte-length-1.0.4.tgz#f45f150c4c66eee968186505ab93fcbb8ad6bf61"
+
 utf8@2.1.0:
   version "2.1.0"
   resolved "https://registry.yarnpkg.com/utf8/-/utf8-2.1.0.tgz#0cfec5c8052d44a23e3aaa908104e8075f95dfd5"
@@ -10440,6 +10888,10 @@ which-module@^2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/which-module/-/which-module-2.0.0.tgz#d9ef07dce77b9902b8a3a8fa4b31c3e3f7e6e87a"
 
+which-pm-runs@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/which-pm-runs/-/which-pm-runs-1.0.0.tgz#670b3afbc552e0b55df6b7780ca74615f23ad1cb"
+
 which@^1.2.14, which@^1.2.9, which@^1.3.0:
   version "1.3.1"
   resolved "https://registry.yarnpkg.com/which/-/which-1.3.1.tgz#a45043d54f5805316da8d62f9f50918d3da70b0a"
@@ -10561,14 +11013,28 @@ xregexp@4.0.0:
   version "4.0.0"
   resolved "https://registry.yarnpkg.com/xregexp/-/xregexp-4.0.0.tgz#e698189de49dd2a18cc5687b05e17c8e43943020"
 
-xtend@^4.0.0, xtend@^4.0.1, xtend@~4.0.1:
+xtend@^4.0.0, xtend@^4.0.1, xtend@~4.0.0, xtend@~4.0.1:
   version "4.0.1"
   resolved "https://registry.yarnpkg.com/xtend/-/xtend-4.0.1.tgz#a5c6d532be656e23db820efb943a1f04998d63af"
 
+xtend@~3.0.0:
+  version "3.0.0"
+  resolved "https://registry.yarnpkg.com/xtend/-/xtend-3.0.0.tgz#5cce7407baf642cba7becda568111c493f59665a"
+
 y-array@^10.1.4:
   version "10.1.4"
   resolved "https://registry.yarnpkg.com/y-array/-/y-array-10.1.4.tgz#e131a5b030d6dcbca10268d4293ecf44bdae7b34"
 
+y-leveldb@^0.0.3:
+  version "0.0.3"
+  resolved "https://registry.yarnpkg.com/y-leveldb/-/y-leveldb-0.0.3.tgz#67390503e254682a63132c73667bbbee098cd39e"
+  dependencies:
+    level "^1.4.0"
+    level-sublevel "^6.5.4"
+    leveldown "^1.7.0-0"
+    levelup "^1.0.0-4"
+    mkdirp "^0.5.1"
+
 y-memory@^8.0.0, y-memory@^8.0.9:
   version "8.0.9"
   resolved "https://registry.yarnpkg.com/y-memory/-/y-memory-8.0.9.tgz#551af9ca153bd344647663b91ebde59a6802b23b"