es6-recap.md

ES6 Recap

ES6 Recap

ES6 Recap

We've just learned a bunch of ES6.

We've learned:

Use const and let instead of var

Remember, When declaring variables using ES6 syntax, if you need to declare a variable whose value will not change, declare it as a const. If the variable's value will or might change, unless you need a global scope, you'll likely declare it as a let.

Use the arrow function => to declare a function

const addTwo = num => {
 return num + 2;
}

Use the arrow function => with implicit returns to declare a function that only returns something

const addTwo = num => num + 2;

Use the arrow function => preserves the original this context

function eatBreakfast(pancakes) {
  var that = this;
  that.food = 'Knife please?';
  Waiter.bringCutlery(function (silverware) {
    that.food = silverware;
  });
}

is now

const eatBreakfast = pancakes => {
  this.food = 'Knife please?';
  Waiter.bringCutlery((silverware) => this.food = silverware);
}

Use literals for assigning a variable as the value of the key of the same name

The second piece of code is synonymous with the first piece of code. The second piece of code saves you from writing price: price when you're declaring an object key-value pair inside an object.

 const price = 100;
 const item = {price: price};

 const price = 100;
 const item = {price};

Use template literals for string interpolation

Remember, these require you to use the tick ``` quotation mark. The single quote or double-quote marks won't invoke string interpolation.

 const greeting = name => `Hi, ${name}.`;