`trimLeft` and `trimRight` (discouraged)

[ddbeck]

Specification

• https://tc39.es/ecma262/multipage/additional-ecmascript-features-for-web-browsers.html#String.prototype.trimleft
• https://tc39.es/ecma262/multipage/additional-ecmascript-features-for-web-browsers.html#String.prototype.trimright

Description

They are aliases to trimStart() and trimEnd(), respectively.

For discouragement, this in Annex B. They're legacy aliases and shouldn't be used.

Documentation

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/trimEnd#browser_compatibility

Discovered in the course of evaluating #4300.

Browser support

This data is under javascript.builtins.String.trim{Start,End} (e.g., MDN table). The first step here will be to break that data up (separately spec'd features should have separate keys in BCD, not alternative_name values).

[ddbeck]

I sent mdn/browser-compat-data#30520 upstream.