JavaScript_Succinctly

It is more common to see an array defined using the literal syntax, but it should be
noted that this shortcut is merely concealing the use of the Array() constructor.
Notes
In practice, the array literal is typically all you will ever need.
Regardless of how an array is defined, if you do not provide any predefined values to
the array, it will still be created but will simply contain no values.
Adding and updating values in arrays
A value can be added to an array at any index, at any time. In the sample that follows,
we add a value to the numeric index 50 of an empty array. What about all the indexes
before 50? Well, like I said, you can add a value to an array at any index, at any time.
But if you add a value to the numeric index 50 of an empty array, JavaScript will fill in all
of the necessary indexes before it with undefined values.
Sample: sample136.html
var myArray = [];
myArray[50] = 'blue';
console.log(myArray.length); /* Logs 51 (0 is counted) because JS created
values 0 to 50 before "blue".*/
Additionally, considering the dynamic nature of JavaScript and the fact that JavaScript
is not strongly typed, an array value can be updated at any time and the value
contained in the index can be any legal value. In the following sample, I change the
value at the numeric index 50 to an object.
Sample: sample137.html
var myArray = [];
myArray[50] = 'blue';
myArray[50] = { 'color': 'blue' }; // Change object type from string to
Object() object.
console.log(myArray[50]); // Logs 'Object {color="blue"}'.
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