Upgrade to Pro — share decks privately, control downloads, hide ads and more …

Javascript: Understanding the weird parts

Javascript: Understanding the weird parts

Javascript started out as a language used to make web pages dynamic, now Javascript runs almost everywhere. The sad part is that a lot of developers only learnt javascript to get things done and don't have an understanding of what happens under the hood. In this presentation, I talk about a few of the nuances of Javascript that give developers the popular "that's weird!" moments.

Presented at Cotta & Cush Tech Talks
Tech Talks is a weekly internal event at Cotta & Cush Limited featuring technical presentations, app reviews among other discussions

Avatar for Adeyemi Olaoye

Adeyemi Olaoye

June 16, 2017
Tweet

More Decks by Adeyemi Olaoye

Other Decks in Programming

Transcript

  1. var a; console.log(a); if (a === undefined) { console.log('a is

    undefined!'); } else { console.log('a is defined!'); }
  2. var Tony = { firstname: 'Tony', lastname: 'Alicea', address: {

    street: '111 Main St.', city: 'New York', state: 'NY' }, fullname: function(){ return firstname + ‘ ’ + lastname; } }; var firstnameKey = ‘firstname’; console.log(Tony.firstnameKey); console.log(Tony.firstname); console.log(Tony.fullname);
  3. function a() { console.log(this); this.newvariable = 'hello'; } var b

    = function() { console.log(this); } a(); console.log(newvariable); // not good!
  4. var foo = function() { var bar = 'baz' return

    { bar: bar } } console.log(foo());