format-json

@saykit/format-json

JSON file formatter for SayKit.

Writes one JSON catalogue per locale — the de facto format for web i18n (react-intl, FormatJS, i18next, …). Reach for this instead of @saykit/format-po when you want plain JSON bundles with no Gettext tooling.

Install

pnpm add -D @saykit/format-json

Usage

import json from '@saykit/format-json';

// inside a bucket:
formatter: json();

Each catalogue is a pretty-printed, flat map keyed by the message id (falling back to a stable content hash when a message has no id — the same key the runtime resolves), with the translation as the value:

{
  "greeting": "Hello"
}

ICU MessageFormat strings are stored verbatim as JSON string values — JSON escaping is handled for you.

Dialects

The plain layout above is just { key: value }, so it drops comments, context, and source references. Pass dialect to keep them using a richer — but still standard — JSON layout:

• dialect: 'arb' — Application Resource Bundle (Flutter/Dart intl). Strings stay flat; each key's metadata lives in a sibling @key object.
• dialect: 'webextension' — the Chrome/WebExtension messages.json shape, where each key maps to a { message, description } object.

formatter: json({ dialect: 'arb' });

{
  "@@locale": "fr",
  "greeting": "Bonjour",
  "@greeting": {
    "description": "A friendly hello",
    "x-saykit-context": "formal",
    "x-saykit-references": ["src/app.ts:10"]
  }
}

Both formats carry translator comments in their native description field. Context and source references have no standard slot, so SayKit round-trips them through x-saykit-context / x-saykit-references extension fields — other tooling reads the description and safely ignores the rest.

Options

• dialect (default none): 'arb' or 'webextension', see above.
• includeReferences (default true): include x-saykit-references source references. No effect on the plain layout, which carries no metadata.
• includeLineNumbers (default true): include line numbers in those references.

Note

JSON catalogues are keyed by message id, so give your messages explicit ids to get stable, human-readable keys. The plain layout carries no source references, comments, or contexts — it is a lean runtime format.

Documentation

See saykit.js.org/core-concepts/formats.