Why Can't Direcrlty Return A Value By Using .push() In Javascript?

using below flatten function as example, why cant I use return directly on the accumulator. Push() function flatten(array){ return reduce(array,function(accumulator, value){

Solution 1:

The push method returns the new length of the Array.

MDN documentation for push

The concat method returns a brand new array containing a combination of the two arrays.

MDN documentation for concat

Solution 2:

If you want a somewhat 'odd' solution that will mean you can return on the same line, you could do this: return (accumulator.push(value1) + 1) && accumulator;

The +1 is to ensure an index of 0 is turned true.

Like I sad, it allows you to return on the line you want, but with odd code. Might suit you case maybe?

But it seems what you'd want to use is concat