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ts-transformer

npm version

Process string messages for translation from modules that use react-intl, specifically:

  • Parse and verify that messages are ICU-compliant w/o any syntax issues.
  • Remove description from message descriptor to save bytes since it isn't used at runtime.
  • Option to remove defaultMessage from message descriptor to save bytes since it isn't used at runtime.
  • Automatically inject message ID based on specific pattern.

Installation

npm i @formatjs/ts-transformer

Usage

The default message descriptors for the app's default language will be processed from: defineMessages(), defineMessage(), intl.formatMessage and <FormattedMessage>; all of which are named exports of the React Intl package.

Via ts-loader

import {transform} from '@formatjs/ts-transformer'

module.exports = {
...otherConfigs,
module: {
rules: [
{
test: /\.tsx?$/,
use: [
{
loader: 'ts-loader',
options: {
getCustomTransformers() {
return {
before: [
transform({
overrideIdFn: '[sha512:contenthash:base64:6]',
}),
],
}
},
},
},
],
},
],
},
}

Via ts-jest in jest.config.js

caution

This requires ts-jest@26.4.0 or later

// jest.config.js
module.exports = {
// [...]
globals: {
'ts-jest': {
astTransformers: {
before: [
{
path: '@formatjs/ts-transformer/ts-jest-integration',
options: {
// options
overrideIdFn: '[sha512:contenthash:base64:6]',
ast: true,
},
},
],
},
},
},
}

Via ttypescript

{
"compilerOptions": {
"plugins": [
{
"transform": "@formatjs/ts-transformer",
"import": "transform",
"type": "config",
"overrideIdFn": "[sha512:contenthash:base64:6]",
"ast": true
}
]
}
}

Via rollup-plugin-typescript2

// rollup.config.js
import typescript from 'rollup-plugin-typescript2'
import {transform} from '@formatjs/ts-transformer'

export default {
input: './main.ts',

plugins: [
typescript({
transformers: () => ({
before: [
transform({
overrideIdFn: '[sha512:contenthash:base64:6]',
ast: true,
}),
],
}),
}),
],
}

Options

overrideIdFn

A function with the signature (id: string, defaultMessage: string, description: string|object) => string which allows you to override the ID both in the extracted javascript and messages.

Alternatively, overrideIdFn can be a template string, which is used only if the message ID is empty.

removeDefaultMessage

Remove defaultMessage field in generated js after extraction.

extractSourceLocation

Whether the metadata about the location of the message in the source file should be extracted. If true, then file, start, and end fields will exist for each extracted message descriptors. Defaults to false.

additionalComponentNames

Additional component names to extract messages from, e.g: ['FormattedFooBarMessage']. NOTE: By default we check for the fact that FormattedMessage are imported from moduleSourceName to make sure variable alias works. This option does not do that so it's less safe.

additionalFunctionNames

Additional function names to extract messages from, e.g: ['$formatMessage']. Use this if you prefer to alias formatMessage to something shorter like $t.

pragma

parse specific additional custom pragma. This allows you to tag certain file with metadata such as project. For example with this file:

// @intl-meta project:my-custom-project
import {FormattedMessage} from 'react-intl'
;<FormattedMessage defaultMessage="foo" id="bar" />

and with option {pragma: "@intl-meta"}, we'll parse out // @intl-meta project:my-custom-project into {project: 'my-custom-project'} in the result file.

ast

Pre-parse defaultMessage into AST for faster runtime perf. This flag doesn't do anything when removeDefaultMessage is true.

onMsgExtracted(filePath: string, msgs: MessageDescriptor[])

Callback that gets triggered whenever a message is encountered.

onMetaExtracted(filePath: string, meta: Record<string, string>)

Callback that gets triggered whenever a pragme meta is encountered.

preserveWhitespace

Whether to preserve whitespace and newlines.

Take a look at compile.ts for example in integration.