deepEqual

deepEqual.js

const deepEqual = (a, b) => {
  const isEqual = (a, b) => (a === b);

  const objCompare = (a, b) => {
    for(let k in a) {
      if (typeof b[k] === 'undefined') {
        return false;
      }
      if (!isEqual(a[k], b[k])) {
        return false;
      }
    }
    return true;
  }

  if (typeof a === 'object' && typeof b === 'object') {
      return objCompare(a, b);
  } else {
      return isEqual(a, b);
  }
}

console.log(deepEqual(1, '1')); //false
console.log(deepEqual({a: 'b'}, 1)); //false
console.log(deepEqual({ key: 'value'}, { key: 'value'})); //true
console.log(deepEqual({ key1: 'value1', key2: { key3: 'value3' }}, { key1: 'value1', key2: { key3: 'value3' }})); //false

The last one should return true