in 2015, JavaScript introduced an important new keyword: const.
It has become a common practice to declare arrays using const:
Example
Cannot be Reassigned
An array declared with const cannot be reassigned:
Example
cars = ["Toyota", "Volvo", "Audi"]; // ERROR
Arrays are Not Constants
The keyword const is a little misleading.
It does NOT define a constant array. It defines a constant reference to an array.
Because of this, we can still change the elements of a constant array.
Elements Can be Reassigned
You can change the elements of a constant array:
Example
const cars = ["Saab", "Volvo", "BMW"];
// You can change an element:
cars[0] = "Toyota";
// You can add an element:
cars.push("Audi");
Browser Support
The const keyword is not supported in Internet Explorer 10 or earlier.
The following table defines the first browser versions with full support for the const keyword:
| Chrome 49 | IE 11 / Edge | Firefox 36 | Safari 10 | Opera 36 |
| Mar, 2016 | Oct, 2013 | Feb, 2015 | Sep, 2016 | Mar, 2016 |
If you expect that any of your users runs Internet Explorer 10 or earlier, you should avoid using const.
It will produce a syntax error, and the code will not run.
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