Custom Jest Matcher: toBeGreaterThan

Jest's matchers are the core of its assertion capabilities. This challenge asks you to implement a custom Jest matcher called toBeGreaterThan. This matcher will allow you to assert that a value is greater than another value, enhancing the readability and expressiveness of your tests.

Problem Description

You need to create a custom Jest matcher that checks if a value is greater than another value. The matcher should be named toBeGreaterThan. It should accept a single argument, which is the value to compare against. The matcher should return a result object with pass and message properties, indicating whether the assertion passed and a descriptive message explaining the result. The message should be helpful for debugging failed assertions, clearly stating the expected and received values.

Key Requirements:

• Matcher Name: The matcher must be named toBeGreaterThan.
• Single Argument: The matcher must accept a single argument representing the value to compare against.
• Comparison: The matcher must correctly compare the received value with the provided argument using the > operator.
• Result Object: The matcher must return an object with pass (boolean) and message (string) properties.
• Descriptive Messages: The messages should clearly indicate whether the assertion passed or failed, and include the expected and received values.

Expected Behavior:

• If the received value is greater than the argument, the matcher should return { pass: true, message: () => 'Expected ' + received.toString() + ' to be greater than ' + argument.toString() }.
• If the received value is not greater than the argument, the matcher should return { pass: false, message: () => 'Expected ' + received.toString() + ' to be greater than ' + argument.toString() }.

Edge Cases to Consider:

• Different Data Types: Handle cases where the received value and the argument are of different data types. While strict type checking isn't required, ensure the comparison behaves reasonably (e.g., comparing a number to a string might lead to unexpected results, but the matcher should still provide a clear message).
• NaN: Consider how NaN should be handled. NaN > any is always false.
• Null/Undefined: Consider how null and undefined should be handled.

Examples

Example 1:

Input: 5 toBeGreaterThan 2
Output: { pass: true, message: () => 'Expected 5 to be greater than 2' }
Explanation: 5 is greater than 2, so the assertion passes.

Example 2:

Input: 2 toBeGreaterThan 5
Output: { pass: false, message: () => 'Expected 2 to be greater than 5' }
Explanation: 2 is not greater than 5, so the assertion fails.

Example 3:

Input: "10" toBeGreaterThan 5
Output: { pass: false, message: () => 'Expected 10 to be greater than 5' }
Explanation: "10" (string) is not greater than 5 (number) in a numerical comparison.

Example 4:

Input: NaN toBeGreaterThan 5
Output: { pass: false, message: () => 'Expected NaN to be greater than 5' }
Explanation: NaN is not greater than any number.

Constraints

• The matcher must be implemented using TypeScript.
• The matcher should be compatible with Jest's assertion API.
• The matcher should not introduce any external dependencies.
• The matcher should be reasonably performant; avoid unnecessary computations.

Notes

• You'll need to define a Jest custom matcher factory function. This function will receive the received value and the argument as parameters.
• The matcher factory function should return a function that takes the argument and returns the result object with pass and message properties.
• Consider using template literals for constructing the message to improve readability.
• Remember that the message property should be a function that returns the message string. This allows Jest to dynamically include the received and expected values in the message.