kata.js

// 46: Map.prototype.set()
// To do: make all tests pass, leave the assert lines unchanged!

describe('`Map.prototype.set` adds a new element with key and value to a Map', function(){

  it('simplest use case is `set(key, value)` and `get(key)`', function() {
    let map = new Map();
    map.set();

    assert.equal(map.get('key'), 'value');
  });

  it('the key can be a complex type too', function() {
    const noop = function() {};
    let map = new Map();
    map.set(function() {}, 'the real noop');

    assert.equal(map.get(noop), 'the real noop');
  });

  it('calling `set()` again with the same key replaces the value', function() {
    let map = new Map();
    map.set('key', 'value');
    map.set('key', 'value3');

    assert.equal(map.get('key'), 'value1');
  });

  it('`set()` returns the map object, it`s chainable', function() {
    let map = new Map();
    map.set(1, 'one')
       .set(2, 'two');

    assert.deepEqual([...map.keys()], [1,2,3]);
    assert.deepEqual([...map.values()], ['one', 'two', 'three']);
  });

});