LeetCode Problem 2704 To Be Or Not To Be — LeetCode: 30 Days of JavaScript

Solving Leetcode 30 Days of JavaScript study plan problems

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) {
    function toBe(val2) {
       if (val === val2) {
           return true
       } else {
           throw new Error('Not Equal')
       }
    }

    function notToBe(val2){
        if (val !== val2) {
            return true
        } else {
            throw new Error('Equal')
        }
    }

    return {
        toBe,
        notToBe
    }
};

Inside the expect function, two internal functions are defined:

• function toBe(val2) { ... }: This function checks if the provided val is strictly equal to val2. If they are equal, it returns true. Otherwise, it throws an error with the message 'Not Equal'.
• function notToBe(val2) { ... }: This function checks if the provided val is not strictly equal to val2. If they are not equal, it returns true. Otherwise, it throws an error with the message 'Equal'.

The expect function returns an object with two properties, toBe and notToBe, which hold references to the internal functions toBe and notToBe respectively.

This code essentially provides a simple way to perform checks and assertions in JavaScript code. By using the expect function, along with its toBe and notToBe methods, you can easily test if values are as expected and throw errors if they are not, allowing for a simple testing framework.

SolutionTypeScript:

type ToBeOrNotToBe = {
    toBe: (val: any) => boolean;
    notToBe: (val: any) => boolean;
};

function expect(val: any): ToBeOrNotToBe {
    return {
        toBe: (otherVal: any) => {
            if (val === otherVal) {
                return true;
            } else {
                throw new Error("Not Equal");
            }
        },
        notToBe: (otherVal: any) => {
            if(val !== otherVal) {
                return true;
            } else {
                throw new Error("Equal");
            }
        }
    };
};

Inside the expect function:

• return { ... }: This line returns an object with two properties, toBe and notToBe, where each property is a function.
• toBe: (otherVal: any) => { ... }: This function checks if the val is strictly equal to the otherVal parameter. If they are equal, it returns true; otherwise, it throws an error with the message "Not Equal".
• notToBe: (otherVal: any) => { ... }: This function checks if the val is not strictly equal to the otherVal parameter. If they are not equal, it returns true; otherwise, it throws an error with the message "Equal".

Link to problem:

https://leetcode.com/problems/to-be-or-not-to-be/description/?envType=study-plan-v2&envId=30-days-of-javascript