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1.1.0 • Public • Published


Reactive simplifed multi language locale module that works with Angular, React, Vue or any nodejs based front-end app. The module allows you to have different langauges dictionaries, control styles direction according to selected language, sync the user language with browser localStorage, it also allows your components to listen to language change event.

Getting Started

These instructions will guide you to install and integrate the insta-locale module in your app.


install the module through npm

npm install --save insta-locale


Go the the main file in your app and initialize the locale service, the main file will be main.ts in Angular for example, or index.jsx or index.tsx in React, its required to initialize the store before any of your components starts. In your main file import the getLocaleService function, if you are in typescript also import the LangaugeModel

import { getLocaleService, LangaugeModel } from 'insta-locale';

use the function to get a new reference to locale service

const localeService = getLocaleService();

define languages array

const languagesList: LangaugeModel[] = [
        key: 'en',
        dir: 'ltr',
        dictionary: {
            'appTitle': 'My App',
        key: 'ar',
        dir: 'rtl',
        dictionary: {
            'appTitle': 'تطبيقي',

        key: 'fr',
        dir: 'ltr',
        dictionary: {
            'appTitle': 'mon application',

each language consists of three parameters

Parameter Discription
key the language unique id, can by any string of your preference
dir the language direction, can be ltr for left direction based languages or rtl for right direction based languages
dictionary a json object with pairs of key/value the holds all labels of your app localised according to the language. Dictionaries of all langauges should have the same keys with localised values for each langauge

init the locale service with the following parameters

    languages: languagesList,
    defaultLangaugeKey: 'en',
    saveToBrowser: true,
    productionMode: false

the config consists of four parameters

Parameter Discription Required Default Value
languages array of all your languages objects Yes
defaultLangaugeKey the key of your app default language Yes
saveToBrowser if true , language will be synced to browser localStorage No true
productionMode if true , the app will not write any console warnings No false

Setting the language

The service by default will set the app language to the default language you specified in the config, unless the user has pre-saved language in the browser, it will take the browser saved one. To set the language manually from a component, go to the component where it needs to set the app language, and get instance of the service

import { getLocaleService } from 'insta-locale';
const localeService = getLocaleService();

then use the setLanguage function to set the desired language from your languages list


if saveToBrowser is set to true, you should find the language saved in browser localStorage

Getting the current active langauge

to get the current active language, simple get instance of the service

import { getLocaleService } from 'insta-locale';
const localeService = getLocaleService();

then call the currentLanguage getter

const language = localeService.currentLanguage;

it returns an object of {key: string, dir: string};

Listening to language change

if a component needs to listen to language change, go the component and get instance of the service

import { getLocaleService } from 'insta-locale';
const localeService = getLocaleService();

subscribe to languageChanged observable

localeService.languageChanged.subscribe((lang)=> {

it emits an object of {key: string, dir: string} whenever language changes

Rendering app labels

to render the app labels in your template, go to the component that needs to render labels and get instance of the service

import { getLocaleService } from 'insta-locale';
const localeService = getLocaleService();

then get the label value using the i18n function, for example

const myApplicationName = localeService.118n('appTitle');

the argument of the i18n is any key defined in your dictionary, the above example will return these values in each language according the config we set earlier

Language Value
English (en) "My App"
Arabic (ar) "تطبيقي"
French (fr) "mon application"

in case you passed a key that doesn't exists, it will return the key itself, for example

const myText = localeService.118n('appBodyName');

it will always return appBodyName, and it wil throw a console warning if the you are not in production mode

Rendering app labels with parameters

alot of times you need to add a dynamic value inside your app labels, to do that simply add your variable name in the label surrounded by curly braces, for example:

const languagesList: LangaugeModel[] = [
       key: 'en',
       dir: 'ltr',
       dictionary: {
           'appTitle': 'My App',
           'welcomeMessage: 'Hi {username}, welcome back'

here, the module expects a variable named username to be passed dynamically to the string, to pass the value pass it inside the vars object in the i18n function

const welcomeText = localeService.118n('welcomeMessage',{ username: 'Walid'});

it will return Hi Walid, welcome back;

in case you didn't pass the { username: 'Walid'} argument to i18n it will return the string without the variables and throw a console warning, for example

const welcomeText = localeService.118n('welcomeMessage');

it will return Hi , welcome back;

You can add as much variables as you want to every label in the dictionary.

App Direction

To handle multi app direction its prefered to use a module that allows css nesting like SASS or LESS. The locale module set the class of the app body tag to the language direction, so if you are in rtl language, inspect your body tag in browser and it should be <body class='rtl'>, now in your main style sheets add these rules

body {

    &.rtl {

        direction: rtl; 


    &.ltr {

        direction: ltr;



and you can add any extra rules required for your app. To add specified styling for a component according to app directiom, go to the component styles .rtl & or .ltr &, rules, for example:

 .errorMessage {

     color: red;

     .ltr &{

       border-left: 5px solid red;

     .rtl &{

       border-right: 5px solid red;


and your app will be running in multi directions styles.


We use SemVer for versioning. For the versions available, see the tags on this repository.



This project is licensed under the MIT License - see the file for details

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