Comparison

Equalility in JS :

Source

[Source2](https://developer.mozilla.org/en-US/docs/Web/JavaScript/ Equality_comparisons_and_sameness)

WCode

Javascript has 5 data types that are passed by value: Boolean, null, undefined, String, and Number. We’ll call these primitive types.

Variables that are assigned a non-primitive value are given a reference to that value. That reference points to the object’s location in memory. The variables don’t actually contain the value. Objects are copied by reference instead of by value.

Equality

Comparing

const array1 = [1, 2, 3];
const array2 = [1, 2, 3];

const obj1 = { a: 1 };
const obj2 = { a: 1 };
const obj3 = { a: 1, b: { c: 1 } };
const obj4 = { a: 1, b: { c: 2 } };

function Comparison(first, second) {
  this.first = first;
  this.second = second;
  this.comparison = first === second;
}

console.table([
  new Comparison(0, new String(0)), //0
  new Comparison(0, "0"), //1
  new Comparison("0", new String(0)), //2
  new Comparison(null, undefined), //3
  new Comparison(new String("0"), null), //4
  new Comparison(new String("0"), undefined), //5
  new Comparison({ a: 1 }, { a: 1 }), //6
  new Comparison(obj1, obj1), //7
  new Comparison(obj1, obj2), //8
  new Comparison(obj1, obj3), //9
  new Comparison(obj3, obj4), //10
  new Comparison({ a: { b: 1 } }, { a: { b: 1 } }), //11,
]);

const a = { name: "foo" };
const b = a;
b.age = 30; /// will change a AND b
console.log(a, b);