I was trying to learn some JS from this HTML5 canvas snake game guide.
But I’m stuck at the part with the push:
for (var i = length; i >= 0; i--) {
snake.push({ x: i, y: 0 });
}
Can anyone explain this to me?
Asked
Active
Viewed 38 times
-6
Sebastian Simon
- 14,320
- 6
- 42
- 61
RKJ
- 25
- 3
-
2Is the documentation on sites like MDN not enough? – Luca Kiebel Jun 06 '18 at 19:59
-
1[Arrays - Learn web development | MDN](https://developer.mozilla.org/en-US/docs/Learn/JavaScript/First_steps/Arrays) – Andreas Jun 06 '18 at 19:59
-
It's almost like you didn't even try to look it up: https://www.w3schools.com/jsref/jsref_push.asp – Phil N DeBlanc Jun 06 '18 at 20:00
-
Are you confused about the [object literal syntax](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Object_initializer)? – Sebastian Simon Jun 06 '18 at 20:04
-
I mean the part with the variables in the paranthesis – RKJ Jun 06 '18 at 20:05
-
@RKJ Which one? `i`? `length`? `snake`? – Sebastian Simon Jun 06 '18 at 20:06
-
So there are two things. There is the object initializer (the curly braces and what is in it). This is a short way of making an object with properies `x` which set to the value of `i` and `y` set to `0`. And there is the push method which appends something to an array. That something in this case is the object mentioned before. I guess this is initializing the snake in the top left corner, where it will occupy the squares `0` to `length`, where `length` is likely the initial length of the snake. – GolezTrol Jun 06 '18 at 20:33
1 Answers
1
push is a method which pushes the data at the end of the existing array without having to know the index of your array. so if your data is not for a specific index and can be at the end in stack, just use the push method. the output would be-
old val of array1 : ['ab','bc', 'ca']
array1.push('cz');
new value of array1 : ['ab','bc', 'ca', 'cz']
