@pico-intl-dev/core

Framework-independent i18n core runtime for pico-intl.

Status: stable v1. The core runtime is covered by E2E tests, integration tests, package readiness checks, release coverage gates, and published npm adoption fixtures.

Install

npm install @pico-intl-dev/core

Basic usage

import { createI18n } from '@pico-intl-dev/core';

const i18n = createI18n({
  base: 'en',
  locale: 'en',
  messages: {
    greeting: 'Hello, {{name}}',
    items: '{{count}} item | {{count}} items',
  },
});

i18n.t('greeting', { name: 'Ana' });
i18n.t('items', { count: 3 });

Message formatting

pico-intl core supports ICU-lite formatting for common app copy:

| Use case | Syntax | | --- | --- | | Interpolation | Hello, {{name}} | | Plural | {{count}} item \| {{count}} items | | Select | {{role, select, admin{Admin} user{User} other{Guest}}} | | Number | {value, number} | | Currency | {price, number, ::currency/USD} | | Date | {date, date, ::yMMMd} | | Time | {time, time, ::hm} |

Double braces interpolate values as text. Single braces with a type, such as {price, number, ::currency/USD}, run native Intl formatting.

See message formatting for examples and ICU strategy for the exact support boundary.

Entry points

Use subpath exports when you only need part of the runtime:

import { createI18n } from '@pico-intl-dev/core/runtime';
import { detectLocale } from '@pico-intl-dev/core/detect';
import { formatDate } from '@pico-intl-dev/core/format';
import { getTextDirection } from '@pico-intl-dev/core/rtl';
import { createLocalStorageAdapter } from '@pico-intl-dev/core/storage';

Available subpaths:

| Subpath | Purpose | | --- | --- | | @pico-intl-dev/core | Full public surface | | @pico-intl-dev/core/runtime | createI18n, interpolation, plural/select helpers | | @pico-intl-dev/core/detect | Locale detection and Accept-Language parsing | | @pico-intl-dev/core/format | Number, date, relative, and list formatting helpers | | @pico-intl-dev/core/http | HTTP/CDN locale loader | | @pico-intl-dev/core/namespace | Namespace helpers and lazy namespace loader | | @pico-intl-dev/core/rtl | Direction helpers | | @pico-intl-dev/core/storage | Locale persistence adapters |

Production notes

• The package has zero runtime dependencies.
• Bundle size depends on import path and bundler tree-shaking. Run npm run bench from the repo root for local measurements.
• Message formatting is intentionally ICU-lite, not full FormatJS parity. See message formatting and ICU strategy.
• Use react-intl/FormatJS today if you need full MessageFormat behavior, rich text formatting, message descriptors, exact plural selectors, or nested ICU message trees.

Verification

npm run build:core
npm test
npm run bench