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intl-format-cache

library4.3.1jsnpmunverified

A memoizer factory for Intl format constructors (Intl.NumberFormat, Intl.DateTimeFormat, IntlMessageFormat, IntlRelativeFormat). Current version 4.3.1, part of the FormatJS suite. Creates cache keys via JSON.stringify of arguments, including ordered options keys. Benchmark shows competitive performance vs fast-memoize, especially on get operations. Intended to be used internally by FormatJS packages; direct use may be redundant if using @formatjs/intl. Ships TypeScript declarations. Stable but low churn.

devops

npm install intl-format-cache

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · INTL-FORMAT-CACHE

intl-format-cache

devopsjavascriptv4.3.1

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

default

✓ import memoizeFormatConstructor from 'intl-format-cache'

✗ const { memoizeFormatConstructor } = require('intl-format-cache')

Default export only; named export does not exist.

memoizeFormatConstructor

✓ const memoizeFormatConstructor = require('intl-format-cache')

✗ import { memoizeFormatConstructor } from 'intl-format-cache'

CommonJS require returns the default export directly, not an object.

memoizeFormatConstructor

✓ import memoizeFormatConstructor from 'intl-format-cache'

✗ import * as m from 'intl-format-cache'

Namespace import gives an object with default property: m.default.

Demonstrates memoizing Intl.NumberFormat constructor and reusing cached instances for same locale.

import memoizeFormatConstructor from 'intl-format-cache'; const getNumberFormat = memoizeFormatConstructor(Intl.NumberFormat); const nf1 = getNumberFormat('en'); const nf2 = getNumberFormat('en'); const nf3 = getNumberFormat('fr'); console.log(nf1 === nf2); // true (cached) console.log(nf1 === nf3); // false (different locale) console.log(nf1.format(1000)); // "1,000" console.log(nf3.format(1000)); // "1 000"

Debug

Known issues

deprecatedAs of FormatJS monorepo v3, this package is deprecated in favor of direct use of @formatjs/intl utilities which include caching internally.

fix

Consider using @formatjs/intl which provides built-in memoization.

affects: >=4.0.0

gotchaCache key is created via JSON.stringify(arguments) including options object. Order of keys in options object is normalized but undefined properties or functions will break memoization.

fix

Ensure options objects have stable key order and no undefined values.

affects: *

gotchaThe function passed to memoizeFormatConstructor must be a constructor (newable). Using arrow functions or non-constructable objects will throw.

fix

Only pass Intl.NumberFormat, Intl.DateTimeFormat, etc. or other constructors.

affects: *

gotchaThe memoized function returns the same instance for repeated calls with the same locale/options. Mutating the returned instance will affect subsequent callers.

fix

Do not mutate the returned format instance; treat it as immutable.

affects: *

Errors

Common errors & fixes

Uncaught TypeError: memoizeFormatConstructor is not a function

Using named import or require incorrectly, e.g., import { memoizeFormatConstructor } from 'intl-format-cache'

fix

Use default import: import memoizeFormatConstructor from 'intl-format-cache'

TypeError: Class constructors must be invoked with 'new'

Passing a non-constructable or arrow function as argument to memoizeFormatConstructor

fix

Pass Intl.NumberFormat or similar constructor, not a regular function.

Upgrade

Version history

4.3.1latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

4 hits · last 30 days

node

Resources

githubhttps://github.com/formatjs/formatjs ↗

packageintl-format-cache ↗

homepagehttps://github.com/formatjs/formatjs ↗