Meta: add spellchecking (#3335)

.github/workflows/spellcheck.yml

@@ -0,0 +1,22 @@
+name: 'ecma-262'
+
+on: [pull_request]
+
+jobs:
+  spellcheck:
+    name: 'check for newly-introduced spelling errors'
+    runs-on: ubuntu-latest
+
+    steps:
+      - run: sudo apt-get install aspell
+      - uses: actions/checkout@v3
+        with:
+          # Number of commits to fetch. 0 indicates all history for all branches and tags.
+          # Default: 1
+          fetch-depth: 0
+      - uses: ljharb/actions/node/install@d9f477827ed71a259056764107f74afc29febcae
+        name: 'nvm install lts/* && npm ci'
+        with:
+          node-version: lts/*
+          use-npm-ci: true
+      - run: node scripts/spellcheck.mjs origin/"${GITHUB_BASE_REF}"

.gitignore

@@ -2,6 +2,7 @@ node_modules/
 out/
 vendor/esmeta
 test*.js
+aspell.txt
 
 # lockfiles we don't use are ignored
 npm-shrinkwrap.json

scripts/spellcheck.mjs

@@ -0,0 +1,72 @@
+import { promisify } from 'node:util';
+import { exec } from 'node:child_process';
+const execP = promisify(exec);
+import { writeFile } from 'node:fs/promises';
+
+const MIN_WORD_SIZE = 3;
+
+const BASE_REF = process.argv[2];
+const ASPELL_OPTS = [
+  '--add-html-check=alt,title,caption,variants',
+  '--ignore-case',
+  '--master=en_GB-ize',
+  '--mode=html',
+  '--run-together',
+  '--run-together-limit=99',
+  '--run-together-min=2',
+  'list',
+].join(' ');
+
+function makeDict(words) {
+  return `personal_ws-1.1 en ${words.length}\n${words.join('\n')}`;
+}
+
+function lines(text) {
+  if (text.length === 0) return [];
+  return text.split('\n');
+}
+
+console.log(`base ref: ${BASE_REF}`);
+
+let { stdout } = await execP(`git show "${BASE_REF}":spec.html | aspell ${ASPELL_OPTS} | sort -fu`);
+
+let existingWords = lines(stdout.trim());
+
+let existingComponents = Array.from(new Set(
+  existingWords
+    .flatMap(word => [...word.matchAll(/(?:^[a-z]|[A-Z])[a-z]{2,}/g)])
+    .map(([w]) => w.toLowerCase())
+));
+
+({ stdout } = await execP(`echo ${existingComponents.map(w => JSON.stringify(w)).join(' ')} | aspell ${ASPELL_OPTS} | sort -fu`));
+
+let existingComponentsReduced = lines(stdout.trim());
+
+await writeFile('aspell.txt', makeDict(existingComponentsReduced));
+
+({ stdout } = await execP(`echo ${existingWords.map(w => JSON.stringify(w)).join(' ')} | aspell --personal=./aspell.txt ${ASPELL_OPTS}`));
+
+let novel = [...existingComponentsReduced, ...lines(stdout.trim())].filter(w => w.length >= MIN_WORD_SIZE);
+novel.sort();
+console.log(`\npreviously used novel words: ${novel.join(', ')}`);
+await writeFile('aspell.txt', makeDict(novel));
+
+({ stdout } = await execP(`aspell --personal=./aspell.txt ${ASPELL_OPTS} list <spec.html | sort -u`));
+let misspellings = lines(stdout.trim()).filter(w => w.length >= MIN_WORD_SIZE);
+
+if (misspellings.length > 0) {
+  console.log(`\nmisspellings: ${misspellings.join(', ')}`);
+  let pattern = misspellings.map(w => `-e ${JSON.stringify(w)}`).join(' --or ');
+  ({ stdout } = await execP(`git grep --line-number --column --fixed-strings --only-matching ${pattern} -- spec.html`));
+
+  console.log('');
+
+  let info = lines(stdout.trim());
+  for (let warning of info) {
+    let [match, file, line, col, typo] = warning.match(/^([^:]+):(\d+):(\d+):(.*)$/);
+    let title = 'Potential Typo';
+    let message = `${JSON.stringify(typo)} is not a previously used word or composed of previously used words. Perhaps it is a typo?`;
+    // https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#setting-a-warning-message
+    console.log(`::warning file=${file},line=${line},endLine=${line},col=${col},endColumn=${col + typo.length},title=${title}::${message}`);
+  }
+}