diff --git a/packages/typewiz-core/package.json b/packages/typewiz-core/package.json
index 4f7a8fa..44466d1 100644
--- a/packages/typewiz-core/package.json
+++ b/packages/typewiz-core/package.json
@@ -16,9 +16,13 @@
   ],
   "dependencies": {
     "ajv": "^6.4.0",
+    "md5": "^2.2.1",
     "typescript": ">=2.4.2 <4.0.0"
   },
   "engines": {
     "node": ">= 8.0.0"
+  },
+  "devDependencies": {
+    "@types/md5": "^2.1.33"
   }
 }
diff --git a/packages/typewiz-core/src/apply-types.ts b/packages/typewiz-core/src/apply-types.ts
index d66392d..1c513f9 100644
--- a/packages/typewiz-core/src/apply-types.ts
+++ b/packages/typewiz-core/src/apply-types.ts
@@ -1,9 +1,10 @@
 import * as fs from 'fs';
+import md5 = require('md5');
 import * as path from 'path';
 import * as ts from 'typescript';
 import { getProgram, ICompilerOptions } from './compiler-helper';
 import { applyReplacements, Replacement } from './replacement';
-import { ICollectedTypeInfo, ISourceLocation } from './type-collector-snippet';
+import { ICollectedTypeInfo, IFileTypeInfo, ISourceLocationAndType } from './type-collector-snippet';
 import { TypewizError } from './typewiz-error';
 
 export interface IApplyTypesOptions extends ICompilerOptions {
@@ -15,9 +16,11 @@ export interface IApplyTypesOptions extends ICompilerOptions {
     prefix?: string;
 }
 
-function findType(program?: ts.Program, typeName?: string, sourcePos?: ISourceLocation) {
-    if (program && sourcePos) {
-        const [sourceName, sourceOffset] = sourcePos;
+function findType(program: ts.Program | undefined, typeInfo: string | ISourceLocationAndType) {
+    const typeName = typeof typeInfo === 'string' ? typeInfo : typeInfo[2];
+    const sourceName = typeof typeInfo !== 'string' ? typeInfo[0] : null;
+    const sourceOffset = typeof typeInfo !== 'string' ? typeInfo[1] : null;
+    if (program && sourceName) {
         const typeChecker = program.getTypeChecker();
         let foundType: string | null = null;
         function visit(node: ts.Node) {
@@ -42,16 +45,23 @@ function findType(program?: ts.Program, typeName?: string, sourcePos?: ISourceLo
 
 export function applyTypesToFile(
     source: string,
-    typeInfo: ICollectedTypeInfo,
+    fileTypes: IFileTypeInfo,
     options: IApplyTypesOptions,
     program?: ts.Program,
 ) {
     const replacements = [];
     const prefix = options.prefix || '';
-    for (const [, pos, types, opts] of typeInfo) {
-        const isOptional = source[pos - 1] === '?';
+    let hadChanges = false;
+    for (const key of Object.keys(fileTypes)) {
+        if (!/^\d+$/.test(key)) {
+            continue;
+        }
+        hadChanges = true;
+        const offset = parseInt(key, 10);
+        const isOptional = source[offset - 1] === '?';
+        const { types, parens, thisNeedsComma, thisType } = fileTypes[offset];
         let sortedTypes = types
-            .map(([name, sourcePos]) => findType(program, name, sourcePos))
+            .map((type) => findType(program, type))
             .filter((t) => t)
             .sort();
         if (isOptional) {
@@ -63,34 +73,33 @@ export function applyTypesToFile(
 
         let thisPrefix = '';
         let suffix = '';
-        if (opts && opts.parens) {
-            replacements.push(Replacement.insert(opts.parens[0], '('));
+        if (parens) {
+            replacements.push(Replacement.insert(parens[0], '('));
             suffix = ')';
         }
-        if (opts && opts.thisNeedsComma) {
+        if (thisNeedsComma) {
             suffix = ', ';
         }
-        if (opts && opts.thisType) {
+        if (thisType) {
             thisPrefix = 'this';
         }
-        replacements.push(Replacement.insert(pos, thisPrefix + ': ' + prefix + sortedTypes.join('|') + suffix));
+        replacements.push(Replacement.insert(offset, thisPrefix + ': ' + prefix + sortedTypes.join('|') + suffix));
     }
-    return applyReplacements(source, replacements);
+    return hadChanges ? applyReplacements(source, replacements) : null;
 }
 
 export function applyTypes(typeInfo: ICollectedTypeInfo, options: IApplyTypesOptions = {}) {
-    const files: { [key: string]: typeof typeInfo } = {};
     const program: ts.Program | undefined = getProgram(options);
-    for (const entry of typeInfo) {
-        const file = entry[0];
-        if (!files[file]) {
-            files[file] = [];
-        }
-        files[file].push(entry);
-    }
-    for (const file of Object.keys(files)) {
+    for (const file of Object.keys(typeInfo)) {
+        const fileInfo = typeInfo[file];
         const filePath = options.rootDir ? path.join(options.rootDir, file) : file;
         const source = fs.readFileSync(filePath, 'utf-8');
-        fs.writeFileSync(filePath, applyTypesToFile(source, files[file], options, program));
+        if (md5(source) !== fileInfo.hash) {
+            throw new Error('Hash mismatch! Source file has changed since type information was collected');
+        }
+        const newContent = applyTypesToFile(source, fileInfo, options, program);
+        if (newContent) {
+            fs.writeFileSync(filePath, newContent);
+        }
     }
 }
diff --git a/packages/typewiz-core/src/instrument.spec.ts b/packages/typewiz-core/src/instrument.spec.ts
index 4a51e2c..ad608b5 100644
--- a/packages/typewiz-core/src/instrument.spec.ts
+++ b/packages/typewiz-core/src/instrument.spec.ts
@@ -10,19 +10,26 @@ describe('instrument', () => {
     it('should instrument function parameters without types', () => {
         const input = `function (a) { return 5; }`;
         expect(instrument(input, 'test.ts')).toContain(
-            astPrettyPrint(`function (a) { $_$twiz("a", a, 11, "test.ts", "{}"); return 5; }`),
+            astPrettyPrint(
+                `function (a) { $_$twiz(a, 11, "test.ts", "{}", "72f01d0740f3f0ac5bd0f708b639b578"); return 5; }`,
+            ),
         );
     });
 
     it('should instrument function with two parameters', () => {
         const input = `function (a, b) { return 5; }`;
-        expect(instrument(input, 'test.ts')).toContain(astPrettyPrint(`$_$twiz("b", b, 14, "test.ts", "{}");`).trim());
+        expect(instrument(input, 'test.ts')).toContain(
+            astPrettyPrint(`$_$twiz(b, 14, "test.ts", "{}", "e1579a22f084265f8fb450beba126b53");`).trim(),
+        );
     });
 
     it('should instrument class method parameters', () => {
         const input = `class Foo { bar(a) { return 5; } }`;
         expect(instrument(input, 'test.ts')).toContain(
-            astPrettyPrint(`class Foo { bar(a) { $_$twiz("a", a, 17, "test.ts", "{}"); return 5; } }`),
+            astPrettyPrint(
+                // tslint:disable-next-line:max-line-length
+                `class Foo { bar(a) { $_$twiz(a, 17, "test.ts", "{}", "d8797d533a93b14ff250fc6b33511db2"); return 5; } }`,
+            ),
         );
     });
 
@@ -40,7 +47,7 @@ describe('instrument', () => {
         const input = `function (a) { return 5; }`;
         expect(instrument(input, 'test.ts')).toContain(
             astPrettyPrint(
-                `declare function $_$twiz(name: string, value: any, pos: number, filename: string, opts: any): void`,
+                `declare function $_$twiz(value: any, pos: number, filename: string, opts: any, hash: string): void`,
             ),
         );
     });
@@ -59,7 +66,7 @@ describe('instrument', () => {
                     instrumentCallExpressions: true,
                     skipTwizDeclarations: true,
                 }),
-            ).toMatch(`foo($_$twiz.track(bar, "test.ts", 4))`);
+            ).toMatch(`foo($_$twiz.track(bar, "test.ts", 4, "82792dee0fbe844bbbea67736c26447d"))`);
         });
 
         it('should not instrument numeric arguments in function calls', () => {
diff --git a/packages/typewiz-core/src/integration.spec.ts b/packages/typewiz-core/src/integration.spec.ts
index 6c0c39b..cb65557 100644
--- a/packages/typewiz-core/src/integration.spec.ts
+++ b/packages/typewiz-core/src/integration.spec.ts
@@ -13,7 +13,12 @@ jest.doMock('fs', () => mockFs);
 
 import { applyTypes, getTypeCollectorSnippet, IApplyTypesOptions, IInstrumentOptions, instrument } from './index';
 
-function typeWiz(input: string, typeCheck = false, options?: IApplyTypesOptions) {
+interface IIntegrationTestOptions {
+    typeCheck?: boolean;
+    applyTwice?: boolean;
+}
+
+function typeWiz(input: string, options?: IApplyTypesOptions & IIntegrationTestOptions) {
     // setup options to allow using the TypeChecker
     if (options && options.tsConfig) {
         options.tsCompilerHost = virtualCompilerHost(input, 'c:/test.ts');
@@ -34,11 +39,12 @@ function typeWiz(input: string, typeCheck = false, options?: IApplyTypesOptions)
     } as IInstrumentOptions);
 
     // Step 2: compile + add the type collector
-    const compiled = typeCheck
-        ? transpileSource(instrumented, 'test.ts')
-        : ts.transpile(instrumented, {
-              target: ts.ScriptTarget.ES2015,
-          });
+    const compiled =
+        options && options.typeCheck
+            ? transpileSource(instrumented, 'test.ts')
+            : ts.transpile(instrumented, {
+                  target: ts.ScriptTarget.ES2015,
+              });
 
     // Step 3: evaluate the code, and collect the runtime type information
     const collectedTypes = vm.runInNewContext(getTypeCollectorSnippet() + compiled + ';$_$twiz.get();');
@@ -48,6 +54,10 @@ function typeWiz(input: string, typeCheck = false, options?: IApplyTypesOptions)
     mockFs.writeFileSync.mockImplementationOnce(() => 0);
 
     applyTypes(collectedTypes, options);
+    if (options && options.applyTwice) {
+        mockFs.readFileSync.mockReturnValue(mockFs.writeFileSync.mock.calls[0][1]);
+        applyTypes(collectedTypes, options);
+    }
 
     if (options && options.tsConfig) {
         expect(options.tsConfigHost!.readFile).toHaveBeenCalledWith(options.tsConfig);
@@ -81,7 +91,7 @@ describe('function parameters', () => {
             greeter.sayGreeting();
         `;
 
-        expect(typeWiz(input, true, { tsConfig: 'tsconfig.integration.json' })).toBe(`
+        expect(typeWiz(input, { typeCheck: true, tsConfig: 'tsconfig.integration.json' })).toBe(`
             class Greeter {
                 text = "Hello World";
                 sayGreeting = greet;
@@ -107,7 +117,7 @@ describe('function parameters', () => {
             greeter.sayGreeting('user');
         `;
 
-        expect(typeWiz(input, true, { tsConfig: 'tsconfig.integration.json' })).toBe(`
+        expect(typeWiz(input, { typeCheck: true, tsConfig: 'tsconfig.integration.json' })).toBe(`
             class Greeter {
                 text = "Hello World: ";
                 sayGreeting = greet;
@@ -134,7 +144,7 @@ describe('function parameters', () => {
             const greeter = new Greeter();
             greeter.sayGreeting();
         `;
-        expect(typeWiz(input, true, { tsConfig: 'tsconfig.integration.json' })).toBe(`
+        expect(typeWiz(input, { typeCheck: true, tsConfig: 'tsconfig.integration.json' })).toBe(`
             class Greeter {
                 text: string;
                 constructor(){
@@ -157,7 +167,7 @@ describe('function parameters', () => {
             greet('World');
         `;
 
-        expect(typeWiz(input, true)).toBe(`
+        expect(typeWiz(input, { typeCheck: true })).toBe(`
             function greet(c: string) {
                 return 'Hello ' + c;
             }
@@ -314,7 +324,7 @@ describe('function parameters', () => {
             f(arr);
         `;
 
-        expect(typeWiz(input, false, { tsConfig: 'tsconfig.integration.json' })).toBe(`
+        expect(typeWiz(input, { tsConfig: 'tsconfig.integration.json' })).toBe(`
             function f(a: string[]) {
             }
 
@@ -333,7 +343,7 @@ describe('function parameters', () => {
             f(promise);
         `;
 
-        expect(typeWiz(input, true, { tsConfig: 'tsconfig.integration.json' })).toBe(`
+        expect(typeWiz(input, { typeCheck: true, tsConfig: 'tsconfig.integration.json' })).toBe(`
             function f(a: Promise<number>) {
                 return a;
             }
@@ -353,7 +363,7 @@ describe('function parameters', () => {
             f(val);
         `;
 
-        expect(typeWiz(input, true, { tsConfig: 'tsconfig.integration.json' })).toBe(`
+        expect(typeWiz(input, { typeCheck: true, tsConfig: 'tsconfig.integration.json' })).toBe(`
             function f(a: {}) {
                 return a;
             }
@@ -436,7 +446,7 @@ describe('class fields', () => {
             const foo = new Foo();
         `;
 
-        expect(typeWiz(input, true)).toBe(`
+        expect(typeWiz(input, { typeCheck: true })).toBe(`
             class Foo {
                 readonly someValue: number;
                 constructor() {
@@ -550,8 +560,21 @@ describe('regression tests', () => {
     });
 });
 
-describe('apply-types options', () => {
-    describe('prefix', () => {
+describe('apply-types behavior', () => {
+    it('should fail with an exception when invoked twice', () => {
+        const input = `
+            function greet(name) {
+                return 'Hello, ' + name;
+            }
+            greet('Uri');
+        `;
+
+        expect(() => typeWiz(input, { applyTwice: true })).toThrowError(
+            'Hash mismatch! Source file has changed since type information was collected',
+        );
+    });
+
+    describe('prefix option', () => {
         it('should add the given prefix in front of the detected types', () => {
             const input = `
                 function greet(c) {
@@ -560,7 +583,7 @@ describe('apply-types options', () => {
                 greet('World');
             `;
 
-            expect(typeWiz(input, false, { prefix: '/*auto*/' })).toBe(`
+            expect(typeWiz(input, { prefix: '/*auto*/' })).toBe(`
                 function greet(c: /*auto*/string) {
                     return 'Hello ' + c;
                 }
diff --git a/packages/typewiz-core/src/transformer.ts b/packages/typewiz-core/src/transformer.ts
index 84246ba..162b94c 100644
--- a/packages/typewiz-core/src/transformer.ts
+++ b/packages/typewiz-core/src/transformer.ts
@@ -1,11 +1,12 @@
+import * as md5 from 'md5';
 import * as ts from 'typescript';
 import { IExtraOptions, IInstrumentOptions } from './instrument';
 
 const declaration = `
-    declare function $_$twiz(name: string, value: any, pos: number, filename: string, opts: any): void;
+    declare function $_$twiz(value: any, pos: number, filename: string, opts: any, hash: string): void;
     declare namespace $_$twiz {
-        function track<T>(value: T, filename: string, offset: number): T;
-        function track(value: any, filename: string, offset: number): any;
+        function track<T>(value: T, filename: string, offset: number, hash: string): T;
+        function track(value: any, filename: string, offset: number, hash: string): any;
     }
 `;
 
@@ -112,17 +113,23 @@ function needsThisInstrumentation(
     );
 }
 
-function createTwizInstrumentStatement(name: string, fileOffset: number, filename: string, opts: IExtraOptions) {
+function createTwizInstrumentStatement(
+    name: string,
+    fileOffset: number,
+    filename: string,
+    opts: IExtraOptions,
+    hash: string,
+) {
     return ts.createStatement(
         ts.createCall(
             ts.createIdentifier('$_$twiz'),
             [],
             [
-                ts.createLiteral(name),
                 ts.createIdentifier(name),
                 ts.createNumericLiteral(fileOffset.toString()),
                 ts.createLiteral(filename),
                 ts.createLiteral(JSON.stringify(opts)),
+                ts.createLiteral(hash),
             ],
         ),
     );
@@ -158,6 +165,7 @@ function visitorFactory(
     options: IInstrumentOptions,
     semanticDiagnostics?: ReadonlyArray<ts.Diagnostic>,
 ) {
+    const hash = md5(source.getFullText());
     const visitor: ts.Visitor = (originalNode: ts.Node): ts.Node | ts.Node[] => {
         const node = ts.visitEachChild(originalNode, visitor, ctx);
 
@@ -175,7 +183,7 @@ function visitorFactory(
                 }
 
                 instrumentStatements.push(
-                    createTwizInstrumentStatement('this', node.parameters.pos, source.fileName, opts),
+                    createTwizInstrumentStatement('this', node.parameters.pos, source.fileName, opts, hash),
                 );
             }
 
@@ -191,7 +199,7 @@ function visitorFactory(
                     }
                     const parameterName = getParameterName(param);
                     instrumentStatements.push(
-                        createTwizInstrumentStatement(parameterName, typeInsertionPos, source.fileName, opts),
+                        createTwizInstrumentStatement(parameterName, typeInsertionPos, source.fileName, opts, hash),
                     );
                 }
             }
@@ -223,6 +231,7 @@ function visitorFactory(
                                 arg,
                                 ts.createLiteral(source.fileName),
                                 ts.createNumericLiteral(arg.getStart().toString()),
+                                ts.createLiteral(hash),
                             ],
                         ),
                     );
@@ -281,7 +290,7 @@ function visitorFactory(
                         ),
                     ],
                     ts.createBlock([
-                        createTwizInstrumentStatement(node.name.text, typeInsertionPos, source.fileName, {}),
+                        createTwizInstrumentStatement(node.name.text, typeInsertionPos, source.fileName, {}, hash),
                         // assign value to privatePropName
                         ts.createStatement(
                             ts.createAssignment(
diff --git a/packages/typewiz-core/src/type-collector-snippet.ts b/packages/typewiz-core/src/type-collector-snippet.ts
index 9bc2db7..4581c2b 100644
--- a/packages/typewiz-core/src/type-collector-snippet.ts
+++ b/packages/typewiz-core/src/type-collector-snippet.ts
@@ -3,20 +3,23 @@ import { IExtraOptions } from './instrument';
 class NestError extends Error {}
 
 export type ISourceLocation = [string, number]; /* filename, offset */
+export type ISourceLocationAndType = [string, number, string | null]; /* filename, offset, type */
 
-export type ICollectedTypeEntry = [
-    string /* filename */,
-    number /* offset */,
-    Array<[string | undefined, ISourceLocation | undefined]> /* discovered types */,
-    IExtraOptions
-];
+export interface ICollectedTypeEntry extends IExtraOptions {
+    types: Array<string | ISourceLocationAndType>;
+}
+
+export interface IFileTypeInfo {
+    [key: number]: ICollectedTypeEntry;
+    hash: string;
+}
 
-export type ICollectedTypeInfo = ICollectedTypeEntry[];
+export interface IHashDictionary {
+    [key: string]: string;
+}
 
-interface IKey {
-    filename: string;
-    pos: number;
-    opts: ICollectedTypeInfo;
+export interface ICollectedTypeInfo {
+    [key: string]: IFileTypeInfo;
 }
 
 let typeNameRunning = false;
@@ -130,20 +133,50 @@ function escapeSpecialKey(key: string) {
     }
     return key;
 }
-const logs: { [key: string]: Set<string> } = {};
+
+const collectedTypes: ICollectedTypeInfo = {};
 const trackedObjects = new WeakMap<object, ISourceLocation>();
 
-export function $_$twiz(name: string, value: any, pos: number, filename: string, optsJson: string) {
+function getOrCreateFile(name: string, hash: string) {
+    if (!collectedTypes[name]) {
+        collectedTypes[name] = {
+            hash,
+        };
+    }
+    return collectedTypes[name];
+}
+
+export function $_$twiz(value: any, pos: number, filename: string, optsJson: string, hash: string) {
     const opts = JSON.parse(optsJson) as ICollectedTypeInfo;
-    const objectDeclaration = trackedObjects.get(value);
-    const index = JSON.stringify({ filename, pos, opts } as IKey);
+    const objectDeclaration = trackedObjects.get(value) || null;
     try {
         const typeName = getTypeName(value);
-        if (!logs[index]) {
-            logs[index] = new Set();
+        const fileInfo = getOrCreateFile(filename, hash);
+        if (!fileInfo[pos]) {
+            fileInfo[pos] = {
+                types: [],
+                ...opts,
+            };
+        }
+        const typeOptions = fileInfo[pos].types;
+        if (objectDeclaration) {
+            const [source, offset] = objectDeclaration;
+            if (
+                !typeOptions.find((item) => {
+                    if (typeof item !== 'string') {
+                        const [s, o, t] = item;
+                        return s === source && o === offset && t === typeName;
+                    }
+                    return false;
+                })
+            ) {
+                typeOptions.push([source, offset, typeName]);
+            }
+        } else if (typeName) {
+            if (typeOptions.indexOf(typeName) < 0) {
+                typeOptions.push(typeName);
+            }
         }
-        const typeSpec = JSON.stringify([typeName, objectDeclaration]);
-        logs[index].add(typeSpec);
     } catch (e) {
         if (e instanceof NestError) {
             // simply ignore the type
@@ -156,14 +189,9 @@ export function $_$twiz(name: string, value: any, pos: number, filename: string,
 // tslint:disable:no-namespace
 export namespace $_$twiz {
     export const typeName = getTypeName;
-    export const get = () => {
-        return Object.keys(logs).map((key) => {
-            const { filename, pos, opts } = JSON.parse(key) as IKey;
-            const typeOptions = Array.from(logs[key]).map((v) => JSON.parse(v));
-            return [filename, pos, typeOptions, opts] as ICollectedTypeEntry;
-        });
-    };
-    export const track = (value: any, filename: string, offset: number) => {
+    export const get = () => collectedTypes;
+    export const track = (value: any, filename: string, offset: number, hash: string) => {
+        getOrCreateFile(filename, hash);
         if (value && (typeof value === 'object' || typeof value === 'function')) {
             trackedObjects.set(value, [filename, offset]);
         }
diff --git a/yarn.lock b/yarn.lock
index df076ce..b1be91a 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -672,6 +672,13 @@
     "@types/node" "*"
     "@types/webpack" "*"
 
+"@types/md5@^2.1.33":
+  version "2.1.33"
+  resolved "https://registry.yarnpkg.com/@types/md5/-/md5-2.1.33.tgz#8c8dba30df4ad0e92296424f08c4898dd808e8df"
+  integrity sha512-8+X960EtKLoSblhauxLKy3zzotagjoj3Jt1Tx9oaxUdZEPIBl+mkrUz6PNKpzJgkrKSN9YgkWTA29c0KnLshmA==
+  dependencies:
+    "@types/node" "*"
+
 "@types/mime@*":
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/@types/mime/-/mime-2.0.0.tgz#5a7306e367c539b9f6543499de8dd519fac37a8b"
@@ -1554,6 +1561,11 @@ chardet@^0.7.0:
   resolved "https://registry.yarnpkg.com/chardet/-/chardet-0.7.0.tgz#90094849f0937f2eedc2425d0d28a9e5f0cbad9e"
   integrity sha512-mT8iDcrh03qDGRRmoA2hmBJnxpllMR+0/0qlzjqZES6NdiWDcZkCNAk4rPFZ9Q85r27unkiNNg8ZOiwZXBHwcA==
 
+charenc@~0.0.1:
+  version "0.0.2"
+  resolved "https://registry.yarnpkg.com/charenc/-/charenc-0.0.2.tgz#c0a1d2f3a7092e03774bfa83f14c0fc5790a8667"
+  integrity sha1-wKHS86cJLgN3S/qD8UwPxXkKhmc=
+
 chokidar@^2.0.3:
   version "2.0.4"
   resolved "https://registry.yarnpkg.com/chokidar/-/chokidar-2.0.4.tgz#356ff4e2b0e8e43e322d18a372460bbcf3accd26"
@@ -1969,6 +1981,11 @@ cross-spawn@^6.0.0:
     shebang-command "^1.2.0"
     which "^1.2.9"
 
+crypt@~0.0.1:
+  version "0.0.2"
+  resolved "https://registry.yarnpkg.com/crypt/-/crypt-0.0.2.tgz#88d7ff7ec0dfb86f713dc87bbb42d044d3e6c41b"
+  integrity sha1-iNf/fsDfuG9xPch7u0LQRNPmxBs=
+
 cryptiles@2.x.x:
   version "2.0.5"
   resolved "https://registry.yarnpkg.com/cryptiles/-/cryptiles-2.0.5.tgz#3bdfecdc608147c1c67202fa291e7dca59eaa3b8"
@@ -3429,7 +3446,7 @@ is-binary-path@^1.0.0:
   dependencies:
     binary-extensions "^1.0.0"
 
-is-buffer@^1.1.5:
+is-buffer@^1.1.5, is-buffer@~1.1.1:
   version "1.1.6"
   resolved "https://registry.yarnpkg.com/is-buffer/-/is-buffer-1.1.6.tgz#efaa2ea9daa0d7ab2ea13a97b2b8ad51fefbe8be"
   integrity sha512-NcdALwpXkTm5Zvvbk7owOUSvVvBKDgKP5/ewfXEznmQFfs4ZRmanOeKBTjRVjka3QFoN6XJ+9F3USqfHqTaU5w==
@@ -4706,6 +4723,15 @@ matcher@^1.0.0:
   dependencies:
     escape-string-regexp "^1.0.4"
 
+md5@^2.2.1:
+  version "2.2.1"
+  resolved "https://registry.yarnpkg.com/md5/-/md5-2.2.1.tgz#53ab38d5fe3c8891ba465329ea23fac0540126f9"
+  integrity sha1-U6s41f48iJG6RlMp6iP6wFQBJvk=
+  dependencies:
+    charenc "~0.0.1"
+    crypt "~0.0.1"
+    is-buffer "~1.1.1"
+
 mem@^1.1.0:
   version "1.1.0"
   resolved "https://registry.yarnpkg.com/mem/-/mem-1.1.0.tgz#5edd52b485ca1d900fe64895505399a0dfa45f76"