ES7 brings two new features

ECMAScript 2016 (more commonly known as ES7). ES7 brings two new features:

1. Array.prototype.includes()
2. New exponential operator: **.


Array.prototype.includes()

We used .indexOf() to know if an element existed in an array. For example:

['my','dad','hates','me'].indexOf('dad')  // 1
// I know it sounds confusing but the value 1 represents
// the index at which the string 'dad' appears in the array.

The key word is “exist.”

.indexOf() is fine if we want to know at which index a given element appears.
But if our goal is to know if a given element exists in an array, then .indexOf() is not the best option. And the reason is simple: When querying the existence of something we expect a boolean value, not a number.


Array.prototype.includes() does exactly that. It determines if a given element exists in an array, returning true if it does, false otherwise.

var life = ['mom', 'dad', 'brother']
life.includes('dad')          // true
life.includes('girlfriend')   // false

The Exponential Operator (**)

The operator ** behaves exactly the same way as Math.pow(). It returns the result of raising the first operand to the power of the second (e.g. x ** y).

# x ** y (aka Math.pow(x,y))
> 2 ** 3
8
> 2 ** 'operand'
NaN

That’s it!

You now have the power of ES7! Use it well!