Pushing to multi-dimensional array

Question

I'm having trouble pushing to a multi-dim array, I get the error

_this.fieldRefs[ID].push is not a function

My code is quite simple, so I thought:

this.fieldRefs = this.fieldRefs || []; // init `this.fieldRefs` if it doesn't exist
this.fieldRefs.push(ID); // push the `ID` e.g `0`
this.fieldRefs[ID].push(ref); // add the `ref` to `0` (ref is an ele)

The first two lines work correctly, and this.fieldRefs contains ID eg:

this.fieldRefs = [0]

But the final line is where the error occurs. If I check this.fieldRefs[ID] I do indeed get 0 but I cannot push to 0 index

Answer 1

What you want to do is to assign an array of refs related to an ID.

So if ID will always be a number, instead of pushing this value to an existing array, it would be a better idea to initialize an array in the index defined by that ID. Like this:

this.fieldRefs = this.fieldRefs || []; 
this.fieldRefs[ID] = []; 
this.fieldRefs[ID].push(ref).

What you are doing currently is different, since you are storing the values of ID on consecutive indices in your fieldRefs array, but the indices don't match the ID values.