shortcuts && simple methods

simple.js

1.
// !! double exclamation it returns boolean value true/false
  const array = [0, 1, 2, 3, 0];

  array.filter(num => num > 0); // bad
  array.filter(num => !!num); // good

2.
// It checks first condition is true or not then only move on to the second condition, if both condition is fullfilling then 
// the object spread operator to the parent object
  const obj = { name: 'Jhon' } 
  
  if(obj.name === 'jhon') {  // bad
     obj.age = 29;
  }                           

  const obj = {    // good
    name: 'Jhon', 
    ...(this.name === 'Jhon' && { age: 29 }
   };  

3.
// Swap using array destructure method
let a = 2, b = 1, temp;

temp = a;
a = b;
b = temp; // bad

[a, b] = [b, a]; // good

4. 
// change the data type using Unary operator
let value = '1234';

parseInt(value); // bad

+value //good