[Javascript] Creating an Immutable Object Graph with Immutable.js Map()

Learn how to create an Immutable.Map() through plain Javascript object construction and also via array tuples.

console.clear();
// Can be an object
var map = Immutable.Map({key: "value"});
console.log(map.get("key")); //"value"

// Can be an array
var map = Immutable.Map([["key", {"name": "Zhentian"}]]);
console.log(map.get("key").name); //"Zhentian"

// size prop
console.log(map.size); //1

mocha.setup(‘bdd‘);
const expect = chai.expect; 

function createObjTodos(numTodos) {

  var obj = {}
  _.each(_.range(numTodos), (index) => {
    const todoSequence = String(index+1);
    obj[‘todo‘+todoSequence] = {
      title: ‘Todo ‘+todoSequence,
      value: `Make ${todoSequence} happen`
    };
  });

  return obj;

} 

describe(‘Creating an Immutable Object Graph with Immutable.js Map()‘, () => {

  it(‘should create Map() with matching keys‘, () => {

    const data = {
      "todo1": {
        title: "Todo 1",
        value: "Make it happen"
      },
      "todo2": {
        title: "Todo 2",
        value: "Make it happen"
      }
    }

    let map = Immutable.Map(data);
    expect(map.get("todo1").title).to.equal("Todo 1");

  });

  it(‘should create Map() with keys from array tuples‘, () => {

    let map = Immutable.Map([["todo1", {title: "Todo 1"}]]) // Note the array within array
    expect(map.get("todo1").title).to.equal("Todo 1");

  });

  it(‘should create Map() with matching size to number of keys‘, () => {

    let map = Immutable.Map(createObjTodos(3))
    expect(map.size).to.equal(3);

  });

});

mocha.run();