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JavaScript

Posted by ryanosten
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ryanosten
PHP Development Techdegree Student 29,615 Points

why don't we have to define player?

Question - in the test suite, we make a player object to use in expectation. Im curious why we do not have to define it as a variable? like 'const player: {}'

const expect = require('chai').expect;

describe('checkForShip', function(){ const checkForShip = require('../game_logic/ship_methods').checkForShip;

it('should correctly report no ship at a given players coordinate', function(){

  player = {
    ships: [
      {
        locations: [[0,0]]
      }
    ]
  }

  expect(checkForShip(player, [9, 9])).to.be.false;
});

1 Answer

Rune Andreas Nielsen
Rune Andreas Nielsen
5,354 Points
Rune Andreas Nielsen
Rune Andreas Nielsen
5,354 Points

Hi, Ryanosten.

In JavaScript, if you're not running in 'strict mode', you don't have to declare a variable. The reason is that, if you don't declare it, the JavaScript engine will automatically declare it for you.

If you instead insert 'use strict' in the beginning of your file, the compiler will throw an error if it finds a variable that is not declared.

Note that it is always best that you declare the variables yourself.

If you want more information, you can check out a blog post that I wrote about Scope in JavaScript where I explain why the variables get declared for you, if not in strict mode http://www.constructcode.com/post/javascript-understanding-scope.