i18n-extract

Manage localization with static analysis.

Installation

npm install --save-dev i18n-extract

The problem solved

This module analyses code statically for key usages, such as i18n.t('some.key'), in order to:

• Report keys that are missing
• Report keys that are unused.
• Report keys that are highly duplicated.

E.g. This module works well in conjunction with:

• polyglot.js (marker: 'polyglot.t',)
• webpack and his localisation plugin: i18n-webpack-plugin (marker: 'i18n',)

Supported keys

• static:

i18n('key.static')

• string concatenation:

i18n('key.' + 'concat')

• template string:

i18n(`key.template`)

• dynamic:

i18n(`key.${dynamic}`)

• comment:

/* i18n-extract key.comment */

API

extractFromCode(code, [options])

Parse the code to extract the argument of calls of i18n(key).

• code should be a string.
• Return an array containing keys used.

Example

import {extractFromCode} from 'i18n-extract';
const keys = extractFromCode("const followMe = i18n('b2b.follow');", {
  marker: 'i18n',
});
// keys = ['b2b.follow']

extractFromFiles(files, [options])

Parse the files to extract the argument of calls of i18n(key).

• files can be either an array of strings or a string. You can also use a glob.
• Return an array containing keys used in the source code.

Example

import {extractFromFiles} from 'i18n-extract';
const keys = extractFromFiles([
  '*.jsx',
  '*.js',
], {
  marker: 'i18n',
});

Options

• marker: The name of the internationalized string marker function. Defaults to i18n.
• keyLoc: An integer indicating the position of the key in the arguments. Defaults to 0. Negative numbers, e.g., -1, indicate a position relative to the end of the argument list.
• parser: Enum indicate the parser to use, can be typescript or flow. Defaults to flow.
• babelOptions: A Babel configuration object to allow applying custom transformations or plugins before scanning for i18n keys. Defaults to a config with all babylon plugins enabled.

findMissing(locale, keysUsed)

Report the missing keys. Those keys should probably be translated.

• locale should be a object containing the translations.
• keysUsed should be an array. Containes the keys used in the source code. It can be retrieve with extractFromFiles our extractFromCode.
• Return a report.

Example

import {findMissing} from 'i18n-extract';
const missing = findMissing({
  key1: 'key 1',
}, ['key1', 'key2']);
 
/**
 * missing = [{
 *   type: 'MISSING',
 *   key: 'key2',
 * }];
 */

Plugins

findUnused(locale, keysUsed)

Report the unused key. Those keys should probably be removed.

• locale should be a object containing the translations.
• keysUsed should be an array. Containes the keys used in the source code. It can be retrieve with extractFromFiles our extractFromCode.
• Return a report.

Example

import {findUnused} from 'i18n-extract';
const unused = findUnused({
  key1: 'key 1',
  key2: 'key 2',
}, ['key1']);
 
/**
 * unused = [{
 *   type: 'UNUSED',
 *   key: 'key2',
 * }];
 */

findDuplicated(locale, keysUsed, options)

Report the duplicated key. Those keys should probably be mutualized. The default threshold is 1, it will report any duplicated translations.

• locale should be a object containing the translations.
• keysUsed should be an array. Containes the keys used in the source code. It can be retrieve with extractFromFiles our extractFromCode.
• options should be an object. You can provide a threshold property to change the number of duplicated value before it's added to the report.
• Return a report.

Example

import {findDuplicated} from 'i18n-extract';
const duplicated = findDuplicated({
  key1: 'Key 1',
  key2: 'Key 2',
  key3: 'Key 2',
});
 
/**
 * unused = [{
 *   type: 'DUPLICATED',
 *   keys: [
 *     'key2',
 *     'key3',
 *   ],
 *   value: 'Key 2',
 * }];
 */

forbidDynamic(locale, keysUsed)

Report any dynamic key. It's arguably more dangerous to use dynamic key. They may break.

• locale should be a object containing the translations.
• keysUsed should be an array. Containes the keys used in the source code. It can be retrieve with extractFromFiles our extractFromCode.
• Return a report.

Example

import {forbidDynamic} from 'i18n-extract';
const forbidDynamic = forbidDynamic({}, ['key.*']);
 
/**
 * forbidDynamic = [{
 *   type: 'FORBID_DYNAMIC',
 *   key: 'key.*',
 * }];
 */

flatten(object)

Flatten the object.

• object should be a object.

Example

import {flatten} from 'i18n-extract';
const flattened = flatten({
  key2: 'Key 2',
  key4: {
    key41: 'Key 4.1',
    key42: {
      key421: 'Key 4.2.1',
    },
  },
});
 
/**
 * flattened = {
 *   key2: 'Key 2',
 *   'key4.key41': 'Key 4.1',
 *   'key4.key42.key421': 'Key 4.2.1',
 * };
 */

mergeMessagesWithPO(messages, poInput, poOutput)

Output a new po file with only the messages present in messages. If a message is already present in the poInput, we keep the translation. If a message is not present, we add a new empty translation.

• messages should be an array.
• poInput should be a string.
• poOutput should be a string.

Example

import {mergeMessagesWithPO} from 'i18n-extract';
 
const messages = ['Message 1', 'Message 2'];
mergeMessagesWithPO(messages, 'messages.po', 'messages.output.po');
 
/**
 * Will output :
 * > messages.output.po has 812 messages.
 * > We have added 7 messages.
 * > We have removed 3 messages.
 */

License

MIT