Tooling

`tooling/console-clean`

Pages log no errors and use no deprecated browser APIs, as seen in the console on load and in the main flows.

Why

Console errors are failed requests, uncaught exceptions and broken features that someone has already hit. Deprecated APIs (for example unload handlers, synchronous XHR, document.domain) stop working in a later browser release, usually without notice to the site owner.

Fix

Open the console on each changed page and fix every error at its cause (a missing file, a null reference, a CSP block), not by catching and hiding it. Replace each deprecated API the Issues panel lists. Errors from extensions do not count; errors from your third parties do.

Examples

// bad: hides the error and the broken feature
try { initMap() } catch {}
// good: fix the cause, report what remains
if (mapElement) initMap(mapElement)

Sources

Facts

Id: tooling/console-clean
Severity: minor
Check: browser needs a rendered page: audit --url
Applies to: page
Same problem in: Lighthouse errors-in-console, Lighthouse deprecations
Taught by the skill: fe-lighthouse Lighthouse and PageSpeed
Since version: 0.1.0

Rule file on GitHub

Read it in the terminal

npx github:dawidolko/frontend-skills explain tooling/console-clean