Add basic linter

.github/workflows/tests.yml

@@ -41,6 +41,9 @@ jobs:
     - name: Setup environment
       run: ./script/gh-action-prepare
 
+    - name: Lint assets
+      run: npm run lint
+
     - name: Build assets
       run: bundle exec rails assets:precompile
 

app/assets/javascripts/application_classic.js

@@ -5,4 +5,5 @@
 //= require jquery/dist/jquery
 //= require timeago/jquery.timeago
 
-jQuery.noConflict()
+/* global jQuery */
+jQuery.noConflict();

build.js

@@ -1,14 +1,14 @@
 #!/usr/bin/env node
 
-import babel from '@babel/core'
+import babel from '@babel/core';
-import { createHash } from 'crypto'
+import { createHash } from 'crypto';
-import esbuild from 'esbuild'
+import esbuild from 'esbuild';
-import coffeeScriptPlugin from 'esbuild-coffeescript'
+import coffeeScriptPlugin from 'esbuild-coffeescript';
-import { lessLoader } from 'esbuild-plugin-less'
+import { lessLoader } from 'esbuild-plugin-less';
-import fsPromises from 'fs/promises'
+import fsPromises from 'fs/promises';
-import glob from 'glob'
+import glob from 'glob';
 
-const outdir = 'app/assets/builds'
+const outdir = 'app/assets/builds';
 
 const plugins = [
   coffeeScriptPlugin({
@@ -25,8 +25,8 @@ const plugins = [
     name: 'babel',
     setup (build) {
       build.onEnd(async () => {
-        const esbuildFilepath = `${outdir}/application.js`
+        const esbuildFilepath = `${outdir}/application.js`;
-        const inputSourceMap = JSON.parse(await fsPromises.readFile(`${esbuildFilepath}.map`))
+        const inputSourceMap = JSON.parse(await fsPromises.readFile(`${esbuildFilepath}.map`));
         const options = {
           inputSourceMap,
           minified: true,
@@ -34,23 +34,23 @@ const plugins = [
             ['@babel/preset-env']
           ],
           sourceMaps: true
-        }
+        };
-        const esbuildOutput = await fsPromises.readFile(esbuildFilepath)
+        const esbuildOutput = await fsPromises.readFile(esbuildFilepath);
-        const result = await babel.transformAsync(esbuildOutput, options)
+        const result = await babel.transformAsync(esbuildOutput, options);
-        const filename = 'application.jsout'
+        const filename = 'application.jsout';
-        const outfileBabel = `${outdir}/${filename}`
+        const outfileBabel = `${outdir}/${filename}`;
         result.map.sources = result.map.sources
           // CoffeeScript sourcemap and Esbuild sourcemap combined generates duplicated source paths
-          .map((path) => path.replace(/\.\.\/\.\.\/javascript(\/.+)?\/app\/javascript\//, '../app/javascript/'))
+          .map((path) => path.replace(/\.\.\/\.\.\/javascript(\/.+)?\/app\/javascript\//, '../app/javascript/'));
-        const resultMap = JSON.stringify(result.map)
+        const resultMap = JSON.stringify(result.map);
-        const resultMapHash = createHash('sha256').update(resultMap).digest('hex')
+        const resultMapHash = createHash('sha256').update(resultMap).digest('hex');
 
         return Promise.all([
           // add hash so it matches sprocket output
           fsPromises.writeFile(outfileBabel, `${result.code}\n//# sourceMappingURL=${filename}-${resultMapHash}.map`),
           fsPromises.writeFile(`${outfileBabel}.map`, JSON.stringify(result.map))
-        ])
+        ]);
-      })
+      });
     }
   },
   {
@@ -58,29 +58,29 @@ const plugins = [
     setup (build) {
       build.onEnd(async (result) => {
         if (options.analyze) {
-          const analyzeResult = await esbuild.analyzeMetafile(result.metafile)
+          const analyzeResult = await esbuild.analyzeMetafile(result.metafile);
 
-          console.log(analyzeResult)
+          console.log(analyzeResult);
         }
-      })
+      });
     }
   }
-]
+];
 
-const args = process.argv.slice(2)
+const args = process.argv.slice(2);
 const options = {
   watch: args.includes('--watch'),
   analyze: args.includes('--analyze')
-}
+};
 const watch = options.watch
   ? {
       onRebuild (error) {
         if (error == null) {
-          console.log('Rebuild succeeded')
+          console.log('Rebuild succeeded');
         }
       }
     }
-  : false
+  : false;
 
 esbuild.build({
   bundle: true,
@@ -94,4 +94,4 @@ esbuild.build({
   sourcemap: 'external',
   watch
 }).then(() => console.log('Build succeeded'))
-  .catch((e) => console.debug(e))
+  .catch((e) => console.debug(e));

package.json

@@ -13,10 +13,12 @@
     "jquery": "^3.6.0",
     "js-cookie": "^3.0.1",
     "mousetrap": "^1.6.5",
+    "semistandard": "^17.0.0",
     "timeago": "^1.6.7"
   },
   "scripts": {
-    "build": "./build.js"
+    "build": "./build.js",
+    "lint": "semistandard *.js app/javascript/**/*.js app/assets/javascripts/*.js"
   },
   "type": "module"
 }