About order of execution in JavaScript

Question

https://code.sololearn.com/WRM3cmHYuoC5/?ref=app

Hi everybody,

In my code I used setInterval and within the function fusionate , but I declared fusionate function only After calling setInterval ( I Saw this order in the lesson). is Javascript Reading code from top to bottom or what's the reason that it works I want to understand thx.

Answer 1

because of hoisting in pre-ES6 syntax.

it is like

var fusionate; // declare first

code snippets such as setInterval

fusionate = function() {...} // initiations

this can cause bugs which are hard to debug, so in ES6 we have const keyword which cannot be hoisted

https://code.sololearn.com/W7Qp4YH4XHjJ/?ref=app

https://code.sololearn.com/WldMKAVDQWPQ/?ref=app

Answer 2

Thank you ! I'm going to Learn ES6 syntax.