upper or lower case is ok

.eslintrc.json

@@ -1,19 +1,18 @@
 {
-    "env": {
-        "commonjs": true,
-        "es6": true,
-        "jest": true,
-        "node": true
-    },
-    "extends": "eslint:recommended",
-    "globals": {
-        "Atomics": "readonly",
-        "SharedArrayBuffer": "readonly"
-    },
-    "parserOptions": {
-        "ecmaVersion": 2018,
-        "sourceType": "module"
-    },
-    "rules": {
-    }
-}
+  "env": {
+    "commonjs": true,
+    "es6": true,
+    "jest": true,
+    "node": true
+  },
+  "extends": "eslint:recommended",
+  "globals": {
+    "Atomics": "readonly",
+    "SharedArrayBuffer": "readonly"
+  },
+  "parserOptions": {
+    "ecmaVersion": 2018,
+    "sourceType": "module"
+  },
+  "rules": {}
+}

.prettierrc.json

@@ -0,0 +1,10 @@
+{
+  "printWidth": 80,
+  "tabWidth": 2,
+  "useTabs": false,
+  "semi": true,
+  "singleQuote": true,
+  "trailingComma": "all",
+  "bracketSpacing": true,
+  "arrowParens": "avoid"
+}

index.js

@@ -1,65 +1,65 @@
-import fetch from "node-fetch";
-import { getInput, setFailed } from "@actions/core";
-import { context } from "@actions/github";
-import { Octokit } from "@octokit/core";
-import * as core from "@actions/core";
+import fetch from 'node-fetch';
+import { getInput, setFailed } from '@actions/core';
+import { context } from '@actions/github';
+import { Octokit } from '@octokit/core';
+import * as core from '@actions/core';
 
 async function run() {
   try {
-    const githubToken = getInput("github-token");
+    const githubToken = getInput('github-token');
     const octokit = new Octokit({ auth: githubToken });
 
+    if (!(context.payload.comment.body || '').toLowerCase().match(/lgtm/)) {
+      core.debug('nothing to do.');
+      return;
+    }
+
     switch (context.eventName) {
-      case "issue_comment":
-        if(!(context.payload.comment.body || '').match(/lgtm/)){
-          core.debug("nothing to do.");
-          return;
-        }
+      case 'issue_comment':
         break;
-      case "pull_request_review":
-        if(!(context.payload.review.body || '').match(/lgtm/) && context.payload.review.state !== "approved"){
-          core.debug("nothing to do.");
+      case 'pull_request_review':
+        if (context.payload.review.state !== 'approved') {
+          core.debug('nothing to do.');
           return;
         }
         break;
-      case "pull_request_review_comment":
-        if(!(context.payload.comment.body || '').match(/lgtm/)){
-          core.debug("nothing to do.");
-          return;
-        }
+      case 'pull_request_review_comment':
         break;
       default:
-        core.debug("nothing to do.");
+        core.debug('nothing to do.');
         return;
     }
 
-    fetch("https://lgtmoon.herokuapp.com/api/images/random")
-      .then((response) => {
+    fetch('https://lgtmoon.herokuapp.com/api/images/random')
+      .then(response => {
         return response.json();
       })
-      .then((data) => {
+      .then(data => {
         const imageUrl = data.images[0].url;
 
-        if (context.eventName === "issue_comment" || context.eventName === "pull_request_review") {
+        if (
+          context.eventName === 'issue_comment' ||
+          context.eventName === 'pull_request_review'
+        ) {
           octokit.request(
-            "POST /repos/{owner}/{repo}/issues/{issue_number}/comments",
+            'POST /repos/{owner}/{repo}/issues/{issue_number}/comments',
             {
               issue_number: context.issue.number,
               owner: context.repo.owner,
               repo: context.repo.repo,
               body: `![](${imageUrl})`,
-            }
+            },
           );
-        } else if (context.eventName === "pull_request_review_comment") {
+        } else if (context.eventName === 'pull_request_review_comment') {
           octokit.request(
-            "POST /repos/{owner}/{repo}/pulls/{pull_number}/comments/{comment_id}/replies",
+            'POST /repos/{owner}/{repo}/pulls/{pull_number}/comments/{comment_id}/replies',
             {
               owner: context.repo.owner,
               repo: context.repo.repo,
               body: `![](${imageUrl})`,
               pull_number: context.payload.pull_request.number,
               comment_id: context.payload.comment.id,
-            }
+            },
           );
         }
       });

package.json

@@ -5,7 +5,9 @@
   "main": "index.js",
   "scripts": {
     "lint": "eslint .",
-    "prepare": "ncc build index.js -o dist --source-map --license licenses.txt"
+    "format": "prettier --write '**/*.js'",
+    "prepare": "ncc build index.js -o dist --source-map --license licenses.txt",
+    "all": "npm run lint && npm run format && npm run prepare"
   },
   "repository": {
     "type": "git",
@@ -26,6 +28,7 @@
   },
   "devDependencies": {
     "@vercel/ncc": "^0.27.0",
-    "eslint": "^7.20.0"
+    "eslint": "^7.20.0",
+    "prettier": "^2.7.1"
   }
-}
+}