Question

I have a several arrays that I need to concat into a new one. I’m doing this:

function ConcatArrays() {

     var TheNewArray = [];

     function TheConcat(TheArray) { TheNewArray = TheNewArray.concat(TheArray); }

     for (var i = 0; i < SomeArrayOfObjects.length; i++) {

         if (SomeCondition) { TheConcat(SomeArrayOfObjects[i]); }
     }
}

For some reason, TheNewArray is always empty. Is there something I’m missing?

Answer 1

You’re assigning a new array to the local parameter.
This does not affect that variable that you passed as a parameter.

You can add an array to an existing array instance (as opposed to creating a new array) like this:

Array.prototype.push.apply(oldArray, newArray);