[Function, Closure] To Be Or Not To Be

https://leetcode.com/problems/to-be-or-not-to-be/description/

To Be Or Not To Be - LeetCode

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

/**
 * @param {string} val
 * @return {Object}
 */
var expect = function(val) {
    const toBe = (a) => {
        if(val === a) {
            return true;
        } else {
            throw "Not Equal";
        }
    }

    const notToBe = (a) => {
        if(val !== a) {
            return true;
        } else {
            throw "Equal";
        }
    }

    return { toBe, notToBe };
};

/**
 * expect(5).toBe(5); // true
 * expect(5).notToBe(5); // throws "Equal"
 */