charmander-injector

Dependency injector for Node.js written in Vanilla JS

How to use it ?

charmander.register('depenendecy', require('dependency');
module.exports = charmander.inject(['dependency'], function(dependency){
    return dependency.helloWorld();
}, this)();

Use case

You're building an app to get all pokemons around the world starting with an specific char. To do that, you have the following module

var pokemon = require('pokemon'); 
module.exports = {
    getPokemonStartingWith: function(char) {
        var pokemons = pokemon.all(),
            filteredPokemons = pokemons.filter(function(p) {
                return p[0].toUpperCase() === char.toUpperCase();
            });
        return filteredPokemons;
    }
}

In last example, we required the 'pokemon' module to get every pokemon around the world. The function of our module, works as expected, but we know you're a great developer and you want to start testing.

When you started to write the test, you've realized that var pokemon = require('pokemon')' should have been injected somehow, otherwise it won't be possible to test with a mock pokemon module.

Therefore, you need an injector, and that's when charmander-injector does its magic. Let's refactor our module using 🔥 charmander 🔥.

var charmander = require('charmander-injector');
charmander.register('pokemon', require('pokemon'));

module.exports = charmander.inject(
    ['pokemon'], 
    getPokemon
)();

function getPokemon(pokemon) {
    'use strict'
    return function getPokemonStartingWith(char) {
        var pokemons = pokemon.all(),
            filteredPokemons = pokemons.filter(function(p) {
                return p[0].toUpperCase() === char.toUpperCase();
            });
        return filteredPokemons;
    }
}

And this is your test!

var charmander = require('charmander-injector');
charmander.registerMock('pokemon', {
        all: function() {
            return ['dummy pokemon 1', 'aPokemon', 'aaPokemon'];
        }
    });
//The order is important (for now)
var getPokemonStartingWith = require('../example');

describe('example', function() {
    'use strict';

    it('getPokemonsStartingWith x char', function() {

        var result = getPokemonStartingWith('a');

        expect(result).toEqual(['aPokemon', 'aaPokemon']);
    });
});