A JavaScript array is an object subtype that is used in the construction of arrays; which are high-level, list-like objects. You can create an array like this:

See the Pen thecodelog.com - JS Arrays 1 by Deano (@deangilewicz) on CodePen.

but it is more common to create an array in the following way:

See the Pen thecodelog.com - JS Arrays 2 by Deano (@deangilewicz) on CodePen.

You can assign values to index positions in the array like this:

See the Pen thecodelog.com - JS Arrays 3 by Deano (@deangilewicz) on CodePen.

or you can assign values to a named key in the array like this:

See the Pen thecodelog.com - JS Arrays 4 by Deano (@deangilewicz) on CodePen.

You can also assign values when creating an array like this:

See the Pen thecodelog.com - JS Arrays 5 by Deano (@deangilewicz) on CodePen.

Arrays have a zero-based index, so the first item in an array has an index of 0. All arrays have a length property which provides the total number of items in an array.

See the Pen thecodelog.com - JS Arrays 6 by Deano (@deangilewicz) on CodePen.