i18next-scanner

i18next-scanner

Scan your code, extract translation keys/values, and merge them into i18n resource files.

Turns your code

i18n._('Loading...');
i18n._('Backslashes in single quote: \' \\ \'');
i18n._('This is \
a multiline \
string');

i18n.t('car', { context: 'blue', count: 1 }); // output: 'One blue car'
i18n.t('car', { context: 'blue', count: 2 }); // output: '2 blue cars'

<Trans i18nKey="some.key">Default text</Trans>

into resource files

{
  "Loading...": "Wird geladen...", // uses existing translation
  "Backslashes in single quote: ' \\ '": "__NOT_TRANSLATED__", // returns a custom string
  "This is a multiline string": "this is a multiline string", // returns the key as the default value 
  "car": "car",
  "car_blue": "One blue car",
  "car_blue_plural": "{{count}} blue cars",
  "some": {
    "key": "Default text"
  }
}

Notice

There is a major breaking change since v1.0, and the API interface and options are not compatible with v0.x.

Checkout Migration Guide while upgrading from earlier versions.

Features

• Fully compatible with i18next - a full-featured i18n javascript library for translating your webapplication.
• Support react-i18next for parsing the Trans component
• Support Key Based Fallback to write your code without the need to maintain i18n keys. This feature is available since i18next@^2.1.0
• A standalone parser API
• A transform stream that works with both Gulp and Grunt task runner.
• Support custom transform and flush functions.

Installation

npm install --save-dev i18next-scanner

Usage

Standard API

const fs = require('fs');
const Parser = require('i18next-scanner').Parser;

const customHandler = function(key) {
    parser.set(key, '__TRANSLATION__');
};

const parser = new Parser();
const content = '';

// Parse Translation Function
// i18next.t('key');
content = fs.readFileSync('/path/to/app.js', 'utf-8');
parser
    .parseFuncFromString(content, customHandler) // pass a custom handler
    .parseFuncFromString(content, { list: ['i18next.t']}) // override `func.list`
    .parseFuncFromString(content, { list: ['i18next.t']}, customHandler)
    .parseFuncFromString(content); // use default options and handler

// Parse Trans component
content = fs.readFileSync('/path/to/app.jsx', 'utf-8');
parser
    .parseFuncFromString(content, customHandler) // pass a custom handler
    .parseFuncFromString(content); // use default options and handler

// Parse HTML Attribute
// <div data-i18n="key"></div>
content = fs.readFileSync('/path/to/index.html', 'utf-8');
parser
    .parseAttrFromString(content, customHandler) // pass a custom handler
    .parseAttrFromString(content, { list: ['data-i18n'] }) // override `attr.list`
    .parseAttrFromString(content, { list: ['data-i18n'] }, customHandler)
    .parseAttrFromString(content); // using default options and handler

console.log(parser.get());
console.log(parser.get({ sort: true }));
console.log(parser.get('translation:key', { lng: 'en'}));

Transform Stream API

The main entry function of i18next-scanner is a transform stream. You can use vinyl-fs to create a readable stream, pipe the stream through i18next-scanner to transform your code into an i18n resource object, and write to a destination folder.

Here is a simple example showing how that works:

const scanner = require('i18next-scanner');
const vfs = require('vinyl-fs');
const sort = require('gulp-sort');
const options = {
    // See options at https://github.com/i18next/i18next-scanner#options
};
vfs.src(['/path/to/src'])
    .pipe(sort()) // Sort files in stream by path
    .pipe(scanner(options))
    .pipe(vfs.dest('/path/to/dest'));

Alternatively, you can get a transform stream by calling createStream() as show below:

vfs.src(['/path/to/src'])
    .pipe(sort()) // Sort files in stream by path
    .pipe(scanner.createStream(options))
    .pipe(vfs.dest('/path/to/dest'));

Gulp

Now you are ready to set up a minimal configuration, and get started with Gulp. For example:

const gulp = require('gulp');
const sort = require('gulp-sort');
const scanner = require('i18next-scanner');

gulp.task('i18next', function() {
    return gulp.src(['src/**/*.{js,html}'])
        .pipe(sort()) // Sort files in stream by path
        .pipe(scanner({
            lngs: ['en', 'de'], // supported languages
            resource: {
                // the source path is relative to current working directory
                loadPath: 'assets/i18n/{{lng}}/{{ns}}.json',
                
                // the destination path is relative to your `gulp.dest()` path
                savePath: 'i18n/{{lng}}/{{ns}}.json'
            }
        }))
        .pipe(gulp.dest('assets'));
});

Grunt

Once you've finished the installation, add this line to your project's Gruntfile:

grunt.loadNpmTasks('i18next-scanner');

In your project's Gruntfile, add a section named i18next to the data object passed into grunt.initConfig(), like so:

grunt.initConfig({
    i18next: {
        dev: {
            src: 'src/**/*.{js,html}',
            dest: 'assets',
            options: {
                lngs: ['en', 'de'],
                resource: {
                    loadPath: 'assets/i18n/{{lng}}/{{ns}}.json',
                    savePath: 'i18n/{{lng}}/{{ns}}.json'
                }
            }
        }
    }
});

API

There are two ways to use i18next-scanner:

Standard API

const Parser = require('i18next-scanner').Parser;
const parser = new Parser(options);

const code = "i18next.t('key'); ...";
parser.parseFuncFromString(code); 

const jsx = '<Trans i18nKey="some.key">Default text</Trans>';
parser.parseTransFromString(jsx);

const html = '<div data-i18n="key"></div>';
parser.parseAttrFromString(html);

parser.get();

parser.parseFuncFromString

Parse translation key from JS function

parser.parseFuncFromString(content)

parser.parseFuncFromString(content, { list: ['_t'] });

parser.parseFuncFromString(content, function(key, options) {
    options.defaultValue = key; // use key as the value
    parser.set(key, options);
});

parser.parseFuncFromString(content, { list: ['_t'] }, function(key, options) {
    parser.set(key, options); // use defaultValue
});

parser.parseTransFromString

Parse translation key from the Trans component

parser.parseTransFromString(content);

parser.parseTransFromString(content, function(key, options) {
    options.defaultValue = key; // use key as the value
    parser.set(key, options);
});

parser.parseAttrFromString

Parse translation key from HTML attribute

parser.parseAttrFromString(content)

parser.parseAttrFromString(content, { list: ['data-i18n'] });

parser.parseAttrFromString(content, function(key) {
    var defaultValue = key; // use key as the value
    parser.set(key, defaultValue);
});

parser.parseAttrFromString(content, { list: ['data-i18n'] }, function(key) {
    parser.set(key); // use defaultValue
});

parser.get

Get the value of a translation key or the whole i18n resource store

// Returns the whole i18n resource store
parser.get();

// Returns the resource store with the top-level keys sorted by alphabetical order 
parser.get({ sort: true });

// Returns a value in fallback language (@see options.fallbackLng) with namespace and key
parser.get('ns:key');

// Returns a value with namespace, key, and lng
parser.get('ns:key', { lng: 'en' });

parser.set

Set a translation key with an optional defaultValue to i18n resource store

// Set a translation key
parser.set(key);

// Set a translation key with default value
parser.set(key, defaultValue);

// Set a translation key with default value using options
parser.set(key, {
    defaultValue: defaultValue
});

Transform Stream API

var scanner = require('i18next-scanner');
scanner.createStream(options, customTransform /* optional */, customFlush /* optional */);

customTransform

The optional customTransform function is provided as the 2nd argument for the transform stream API. It must have the following signature: function (file, encoding, done) {}. A minimal implementation should call the done() function to indicate that the transformation is done, even if that transformation means discarding the file. For example:

var scanner = require('i18next-scanner');
var vfs = require('vinyl-fs');
var customTransform = function _transform(file, enc, done) {
    var parser = this.parser;
    var content = fs.readFileSync(file.path, enc);

    // add your code
    done();
};

vfs.src(['/path/to/src'])
    .pipe(scanner(options, customTransform))
    .pipe(vfs.dest('path/to/dest'));

To parse a translation key, call parser.set(key, defaultValue) to assign the key with an optional defaultValue. For example:

var customTransform = function _transform(file, enc, done) {
    var parser = this.parser;
    var content = fs.readFileSync(file.path, enc);
    
    parser.parseFuncFromString(content, { list: ['i18n.t'] }, function(key) {
        var defaultValue = '__L10N__';
        parser.set(key, defaultValue);
    });
    
    done();
};

Alternatively, you may call parser.set(defaultKey, value) to assign the value with a default key. The defaultKey should be unique string and can never be null, undefined, or empty. For example:

var hash = require('sha1');
var customTransform = function _transform(file, enc, done) {
    var parser = this.parser;
    var content = fs.readFileSync(file.path, enc);
    
    parser.parseFuncFromString(content, { list: ['i18n._'] }, function(key) {
        var value = key;
        var defaultKey = hash(value);
        parser.set(defaultKey, value);
    });
    
    done();
};

customFlush

The optional customFlush function is provided as the last argument for the transform stream API, it is called just prior to the stream ending. You can implement your customFlush function to override the default flush function. When everything's done, call the done() function to indicate the stream is finished. For example:

var scanner = require('i18next-scanner');
var vfs = require('vinyl-fs');
var customFlush = function _flush(done) {
    var parser = this.parser;
    var resStore = parser.getResourceStore();

    // loop over the resStore
    Object.keys(resStore).forEach(function(lng) {
        var namespaces = resStore[lng];
        Object.keys(namespaces).forEach(function(ns) {
            var obj = namespaces[ns];
            // add your code
        });
    });
    
    done();
};

vfs.src(['/path/to/src'])
    .pipe(scanner(options, customTransform, customFlush))
    .pipe(vfs.dest('/path/to/dest'));

Default Options

Below are the configuration options with their default values:

{
    debug: false,
    removeUnusedKeys: false,
    sort: false,
    attr: {
        list: ['data-i18n'],
        extensions: ['.html', '.htm']
    },
    func: {
        list: ['i18next.t', 'i18n.t'],
        extensions: ['.js', '.jsx']
    },
    lngs: ['en'],
    ns: ['translation'],
    defaultNs: 'translation',
    defaultValue: '',
    resource: {
        loadPath: 'i18n/{{lng}}/{{ns}}.json',
        savePath: 'i18n/{{lng}}/{{ns}}.json',
    },
    nsSeparator: ':',
    keySeparator: '.',
    pluralSeparator: '_',
    contextSeparator: '_',
    interpolation: {
        pefix: '{{',
        suffix: '}}'
    }
}

debug

Type: Boolean Default: false

Set to true to trun on debug output.

removeUnusedKeys

Type: Boolean Default: false

Set to true to remove unused translation keys from i18n resource files.

sort

Type: Boolean Default: false

Set to true if you want to sort translation keys in ascending order.

attr

Type: Object or false

If an Object is supplied, you can either specify a list of attributes and extensions, or override the default.

{ // Default
    attr: {
        list: ['data-i18n'],
        extensions: ['.html', '.htm']
    }
}

You can set attr to false to disable parsing attribute as below:

{
    attr: false
}

func

Type: Object or false

If an Object is supplied, you can either specify a list of translation functions and extensions, or override the default.

{ // Default
    func: {
        list: ['i18next.t', 'i18n.t'],
        extensions: ['.js', '.jsx']
    }
}

You can set func to false to disable parsing translation function as below:

{
    func: false
}

lngs

Type: Array Default: ['en']

An array of supported languages.

ns

Type: String or Array Default: ['translation']

A namespace string or an array of namespaces.

defaultNs

Type: String Default: 'translation'

The default namespace used if not passed to translation function.

defaultValue

Type: String or Function Default: ''

The default value used if not passed to parser.set.

Examples

Provides the default value with a string:

{
    defaultValue: '__NOT_TRANSLATED__'
}

Provides the default value as a callback function:

{
    // @param {string} lng The language currently used.
    // @param {string} ns The namespace currently used.
    // @param {string} key The translation key.
    // @return {string} Returns a default value for the translation key.
    defaultValue: function(lng, ns, key) {
        if (lng === 'en') {
            // Return key as the default value for English language
            return key;
        }
        // Return the string '__NOT_TRANSLATED__' for other languages
        return '__NOT_TRANSLATED__';
    }
}

resource

Type: Object

Resource options:

{ // Default
    resource: {
        // path where resources get loaded from
        loadPath: 'i18n/{{lng}}/{{ns}}.json',

        // path to store resources
        savePath: 'i18n/{{lng}}/{{ns}}.json',

        // jsonIndent to use when storing json files
        jsonIndent: 2
    }
}

keySeparator

Type: String or false Default: '.'

Key separator used in translation keys.

Set to false to disable key separator if you prefer having keys as the fallback for translation (e.g. gettext). This feature is supported by i18next@2.1.0. Also see Key based fallback at http://i18next.com/translate/keyBasedFallback.

nsSeparator

Type: String or false Default: ':'

Namespace separator used in translation keys.

Set to false to disable namespace separator if you prefer having keys as the fallback for translation (e.g. gettext). This feature is supported by i18next@2.1.0. Also see Key based fallback at http://i18next.com/translate/keyBasedFallback.

context

Type: Boolean or Function Default: true

Whether to add context form key.

context: function(lng, ns, key, options) {
    return true;
}

contextFallback

Type: Boolean Default: true

Whether to add a fallback key as well as the context form key.

contextSeparator

Type: String Default: '_'

The character to split context from key.

plural

Type: Boolean or Function Default: true

Whether to add plural form key.

plural: function(lng, ns, key, options) {
    return true;
}

pluralFallback

Type: Boolean Default: true

Whether to add a fallback key as well as the plural form key.

pluralSeparator

Type: String Default: '_'

The character to split plural from key.

interpolation

Type: Object

interpolation options

{ // Default
    interpolation: {
        // The prefix for variables
        prefix: '{{',

        // The suffix for variables
        suffix: '}}'
    }
}

Integration Guide

Checkout Integration Guide to learn how to integrate with React, Gettext Style I18n, and Handlebars.

License

MIT