When pushing an array’s contents to another array I get
“Uncaught TypeError: Cannot read property ‘push’ of undefined” error in this snippet.
var order = new Object(), stack = [];
for(var i=0;i<a.length;i++){
if(parseInt(a[i].daysleft) == 0){ order[0].push(a[i]); }
if(parseInt(a[i].daysleft) > 0){ order[1].push(a[i]); }
if(parseInt(a[i].daysleft) < 0){ order[2].push(a[i]); }
}
Why do I get this error in the second if statement ? Thanks a lot!
8 Answers
You get the error because order[1]
is undefined
.
That error message means that somewhere in your code, an attempt is being made to access a property with some name (here it’s “push”), but instead of an object, the base for the reference is actually undefined
. Thus, to find the problem, you’d look for code that refers to that property name (“push”), and see what’s to the left of it. In this case, the code is
if(parseInt(a[i].daysleft) > 0){ order[1].push(a[i]); }
which means that the code expects order[1]
to be an array. It is, however, not an array; it’s undefined
, so you get the error. Why is it undefined
? Well, your code doesn’t do anything to make it anything else, based on what’s in your question.
Now, if you just want to place a[i]
in a particular property of the object, then there’s no need to call .push()
at all:
var order = [], stack = [];
for(var i=0;i<a.length;i++){
if(parseInt(a[i].daysleft) == 0){ order[0] = a[i]; }
if(parseInt(a[i].daysleft) > 0){ order[1] = a[i]; }
if(parseInt(a[i].daysleft) < 0){ order[2] = a[i]; }
}
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]);
This error occurs in angular when you didn’t intialise the array blank.
For an example:
userlist: any[ ];
this.userlist = [ ];
or
userlist: any = [ ];
In most cases you have to initialize the array,
let list: number[] = [];
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.
You do not need to give an index.
Instead of doing order[0].push(a[i])
, just do order.push(a[i])
.
I fixed in the below way with typescript
- Define and initialize firest
pageNumbers: number[] = [];
-
than populate it
for (let i = 1; i < 201; i++) { this.pageNumbers.push(i); }
order[] is undefined that’s why
Just define order[1]…[n] to = some value
this should fix it