2704. To Be Or Not To Be

Problem

Write a function expect that helps developers test their code. It should take in any value val and return an object with the following two functions.

• toBe(val) accepts another value and returns true if the two values === each other. If they are not equal, it should throw an error "Not Equal".
• notToBe(val) accepts another value and returns true if the two values !== each other. If they are equal, it should throw an error "Equal".

Example 1:

Input: func = () => expect(5).toBe(5)
Output: {"value": true}
Explanation: 5 === 5 so this expression returns true.

Example 2:

Input: func = () => expect(5).toBe(null)
Output: {"error": "Not Equal"}
Explanation: 5 !== null so this expression throw the error "Not Equal".

Example 3:

Input: func = () => expect(5).notToBe(null)
Output: {"value": true}
Explanation: 5 !== null so this expression returns true.

Solution (Javascript)

/**
 * @param {string} val
 * @return {Object}
 */
var expect = function (val) {
  return {
    toBe: (val2) => {
      if (val !== val2) throw new Error("Not Equal");
      else return true;
    },
    notToBe: (val2) => {
      if (val === val2) throw new Error("Equal");
      else return true;
    },
  };
};

/* For example, when expect(5).toBe(4) is called,
   val is the expect parameter (so val equals 5),
   val2 is the toBe parameter (so val2 equals 4).
   Since val !== val2, aka 5 != 4, we throw error "Not Equal". */

Explain:

nope.

Complexity:

• Time complexity : O(n).
• Space complexity : O(n).