Choose the best post translation

Choose the highest-quality translation by locale fallback order, freshness, and stable translation ID.

EasyJavaScript Product Algorithms

30 min0% acceptance

Description

Choose the highest-quality translation by locale fallback order, freshness, and stable translation ID. Implement the learner-facing contract completely and satisfy every observable requirement without relying on hidden infrastructure.

Requirements

Export choosePostTranslation from src/App.js.
Compare locale tags case-insensitively with underscores normalized to hyphens.
Prefer exact requested locale, then its base language, then input.defaultLocale.
Within one locale prefer higher quality and then greater updatedAt.
Break remaining ties by ascending translation ID and return null when no candidate locale matches.
Return an observably equivalent result for equivalent inputs without reading time, randomness, network, storage, or DOM globals.
Do not mutate input objects, arrays, nested records, or values retained in the returned result.

Regional fallback

Input

Requested fr-CA with only fr and en

Expected output

The best fr translation is selected

Explanation

Compare locale tags case-insensitively with underscores normalized to hyphens.

Quality tie

Input

Two en translations share quality

Expected output

The newer translation wins

Explanation

Prefer exact requested locale, then its base language, then input.defaultLocale.

Constraints

Implement a pure synchronous function with no external side effects
Treat every input collection and nested record as read-only
Return JSON-compatible data except where the declared TypeScript API explicitly uses bigint

Hints

Hint 1

Start with the normalizes-locales behavior and make its observable result deterministic.

Hint 2

Model uses-fallback-order independently before combining it with the remaining states.

Hint 3

Verify the boundary described by stable-id-tie-break without changing caller-owned input.

JavaScriptlocalizationranking