2.1 ES6 Enhancements

There are a number of enhancements in the

In web development, a polyfill is code that implements a feature on web browsers that do not support the feature. Most often, it refers to a JavaScript library that implements an HTML5 web standard, either an established standard (supported by some browsers) on older browsers, or a proposed standard (not supported by any browsers) on existing browsers.

Source:

Wikipedia

Block-Scoped Variables (Recap)

We have already seen this previously through the use of let and const. Basically, we are now able to have variables that are declared with block scoping { } instead of function scoping.

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{
  //var1 is only available in this block
  let var1 = 10;
}

//var1 is not available here
console.log(var1); //Error: var1 is not defined

Default Function Parameter Values (Recap)

We have also discussed default function parameters previously. This is achieved by using the assignment (=) syntax.

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//generate a random integer within a range from
//min (inclusive) to max (exclusive)
//default range: [0, 100)
function generateRandomInt(min = 0, max = 100) {
  min = Math.ceil(min);
  max = Math.floor(max);
  return Math.floor(Math.random() * (max - min)) + min;
}

//generate 10 random numbers within range of 0 to 100
for (let i = 0; i < 10; i++) {
  console.log(generateRandomInt());
}

//generate 10 random numbers within range of 0 to 1000
for (let i = 0; i < 10; i++) {
  console.log(generateRandomInt(0, 1000));
}

In the rest of this section, we will elaborate on the following ES6 syntax:

• Arrow Functions
• String Enhancements
• ES6 Class System
• Object Enhancements
• Rest and Spread Operators
• Destructuring
• Promises
• Module System