JavaScript_Succinctly

Using brackets to access the index in the array, then the property
blue.
console.log(myArray[50]['color']); // Logs 'blue'.
// Using dot notation.
console.log(myArray[50].color); // Logs 'blue'.
Length vs. index
An array starts indexing values at zero. This means that the first numeric slot to hold a
value in an array looks like myArray[0]. This can be a bit confusing—if I create an
array with a single value, the index of the value is 0 while the length of the array is 1.
Make sure you understand that the length of an array represents the number of values
contained within the array, while the numeric index of the array starts at zero.
In the following sample, the string value blue is contained in the myArray array at the
numeric index 0, but since the array contains one value, the length of the array is 1.
Sample: sample138.html
var myArray = ['blue'] // The index 0 contains the string value 'blue'.
console.log(myArray[0]); // Logs 'blue'.
console.log(myArray.length); // Logs 1.
Defining arrays with a predefined length
As I mentioned earlier, by passing a single integer parameter to the Array()
constructor, it’s possible to predefine the array’s length, or the number of values it will
contain. In this case, the constructor makes an exception and assumes you want to set
the length of the array and not pre-populate the array with values.
In the next sample, we set up the myArray array with a predefined length of 3. Again,
we are configuring the length of the array, not passing it a value to be stored at the 0
index.
Sample: sample139.html
var myArray = new Array(3);
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