Implement toBeTruthy for Jest

Jest is a popular JavaScript testing framework that provides a rich set of matchers for asserting the expected outcomes of your code. One of these fundamental matchers is toBeTruthy, which checks if a value is "truthy". This challenge asks you to implement a custom Jest matcher that mimics the behavior of expect().toBeTruthy().

Problem Description

Your task is to create a custom Jest matcher named toBeTruthy. This matcher should evaluate whether the received value in an assertion is considered "truthy" in JavaScript. A truthy value is any value that is not falsy. The falsy values in JavaScript are: false, 0, -0, 0n (BigInt zero), "" (empty string), null, undefined, and NaN.

Key Requirements:

• Create a custom matcher function that can be added to Jest's expect.
• The matcher should accept one argument: the received value.
• The matcher should return an object with two properties:
  • pass: A boolean indicating whether the assertion passed (true if the value is truthy, false otherwise).
  • message: A function that returns the error message to be displayed when the assertion fails. This message should clearly state what was expected and what was received.

Expected Behavior:

• If the received value is truthy, the pass property should be true.
• If the received value is falsy, the pass property should be false.
• The message function should provide informative output for both passing and failing scenarios (Jest often handles the "not" cases automatically, but it's good practice to consider them).

Examples

Example 1:

// In your Jest test file:
expect(true).toBeTruthy();
expect(1).toBeTruthy();
expect("hello").toBeTruthy();
expect({}).toBeTruthy();
expect([]).toBeTruthy();

Output (if all assertions pass): No output (tests pass silently).

Explanation: All the provided values (true, 1, "hello", {}, []) are truthy in JavaScript.

Example 2:

// In your Jest test file:
expect(false).not.toBeTruthy();
expect(0).not.toBeTruthy();
expect("").not.toBeTruthy();
expect(null).not.toBeTruthy();
expect(undefined).not.toBeTruthy();
expect(NaN).not.toBeTruthy();

Output (if all assertions pass): No output.

Explanation: All the provided values (false, 0, "", null, undefined, NaN) are falsy in JavaScript, so the not.toBeTruthy() assertion correctly passes.

Example 3: Failing Assertion

// In your Jest test file:
expect(0).toBeTruthy();

Expected Output (if this assertion fails):

    Expected 0 to be truthy.

Explanation: The value 0 is falsy in JavaScript, so the toBeTruthy() matcher should fail, and the error message clearly indicates that 0 was expected to be truthy but wasn't.

Constraints

• The solution must be implemented in TypeScript.
• You will need to use Jest's custom matcher API.
• The message function should generate a human-readable error string.

Notes

• Familiarize yourself with Jest's custom matcher API, particularly how to extend jest.Expect.
• Consider how to handle the this context within your custom matcher.
• The core logic of the matcher will involve checking if a value evaluates to true in a boolean context.
• You'll need to register your custom matcher with Jest.