Cannot read property 'push' of undefined when combining arrays

Question

When pushing an array\'s contents to another array I get

\"Uncaught TypeError: Cannot read property \'push\' of undefined\" error in this snippet.

Answer 1

answer to your question is simple order is not a object make it an array. var order = new Array(); order.push(/item to push/); when ever this error appears just check the left of which property the error is in this case it is push which is order[] so it is undefined.

Answer 2

I fixed in the below way with typescript

1. Define and initialize firest

pageNumbers: number[] = [];

2. than populate it

   for (let i = 1; i < 201; i++) {
       this.pageNumbers.push(i);
   }
   

Answer 3

This error occurs in angular when you didn't intialise the array blank.
For an example:

userlist: any[ ];
this.userlist = [ ]; 

or

userlist: any = [ ];

Answer 4

order is an Object, not an Array().

push() is for arrays.

Refer to this post

Try this though(but your subobjects have to be Arrays()):

var order = new Array();

// initialize order; n = index
order[n] = new Array();

// and then you can perform push()
order[n].push(some_value);

Or you can just use order as an array of non-array objects:

var order = new Array();

order.push(a[n]);

Answer 5

order[] is undefined that's why

Just define order[1]...[n] to = some value

this should fix it

Answer 6

In most cases you have to initialize the array,

let list: number[] = [];