JS Code Guardian

VS Code extension for JavaScript/TypeScript (and some embedded JS/TS cases like Vue/Svelte) that helps you catch syntax/keyword typos, offers one-click fixes, and adds useful inline information.

Features

1) Red diagnostics for keyword / syntax typos

The extension scans code and highlights identifiers that look like JavaScript syntax/keyword typos (example: funciton → function).

• Uses fuzzy matching (Damerau–Levenshtein) with context checks to reduce false positives.
• Shows additional “Correct syntax” info in the diagnostic related information when available.

2) Hover help + “Fix with JS Code Guardian”

When you hover over a highlighted issue, you get:

• Message like: Unknown syntax "..." Did you mean "..."?
• A clickable action: [Fix with JS Code Guardian] (implemented via a trusted VS Code command).

3) One-click Quick Fix

From the diagnostic or Quick Fix menu, the extension performs an edit that replaces the wrong range with the computed fix.

Command id: jsCodeGuardian.fixIssue

4) Dim unused symbols

The extension applies text decorations (opacity) to:

• Unused bindings (variables, imports, functions, classes, parameters)
• Unused object properties in patterns

5) Inline previews for console & popup calls

For calls where the runtime value can be evaluated statically (limited depth), it shows inline hints:

• console.*(...) → inline text preview after the call
• alert(...), confirm(...), prompt(...) → inline popup preview text after the call

Safe built-in methods are evaluated when their inputs are known, including string methods like toUpperCase(), array methods like map(), filter(), join(), slice(), number methods like toFixed(), plus Math.*, Object.keys(), Object.values(), and Array.isArray().

Supported languages

Based on the extension activation and language selectors:

• javascript
• typescript
• javascriptreact
• typescriptreact
• vue
• svelte

How it works (high level)

• Parses source using Babel parser with language-appropriate plugins.
• Uses rules + documentation from: src/dataset/data.json
  • syntax: documentation for known APIs/keywords
  • corrections: typo → fix mappings for keyword/syntax identifiers
• If parsing fails, it falls back to a lightweight tokenization approach to still find likely keyword typos.