The length of array after adding an element on a non-numeric key

Question | May 11, 2017 | nextptr 

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The array colors has 3 elements in it:

var colors = ['Blue','Green','Yellow'];

What will be the effect on its length if an element is added on a non-numeric key as shown below:

colors['red'] = 'Red';
// colors.length ??

What will be the resulting value of colors.length now?