“Map.prototype.getOrInsert” made its way to TC39 Stage 4, use it in “setIfMissing”.

[theengineear]

The https://github.com/tc39/proposal-upsert was just announced at Stage 4 and already has support in FF. Waiting on Chrome and Safari. Currently, we manage this ourselves, but the native behavior should be more performant and carry better semantics.

TODO:

• Shipping in Chrome (ticket)
• Shipping in FF (ticket)
• Shipping in Safari (ticket ??)
• Shipping in TypeScript 6.0 (no need to switch to this ahead of type definitions, there’s no rush)

// before
const analysis = TemplateEngine.#setIfMissing(TemplateEngine.#stringsToAnalysis, strings, () => ({}));

// after
const analysis = TemplateEngine.#stringsToAnalysis.getOrInsertComputed(strings, () => ({}));