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.
The closure-based approach makes use of JavaScript's closure capabilities to encapsulate the comparison logic within the returned object. The main idea here is to utilize closures to maintain the original value passed to the expect function, and then provide methods that perform the respective comparisons. This approach leverages the benefits of closures to maintain a clean and functional interface.
In JavaScript, the expect function returns an object with two methods: toBe and notToBe. These methods use closures to access the value originally passed into expect. When toBe is called, it checks if the values are strictly equal and returns true or throws an error appropriately. Similarly, notToBe checks for inequality and handles it in the same manner. The use of closures allows these methods to always reference the correct original val that expect was called with.
Python
Time Complexity: O(1) for both toBe and notToBe methods as they perform constant time operations.
Space Complexity: O(1) since the space required does not grow with the size of the input.
The class-based approach in languages like C++, C#, and Java exploits object-oriented programming features to achieve encapsulation and method binding. Here, the idea is to define a class that keeps track of the initial value and provides methods that can be invoked on it to perform the required checks. This method is beneficial for languages where closures don't exist or are cumbersome to implement, maintaining a clear object-oriented design.
In C++, the Expect class is used to encapsulate the initial value. The constructor initializes this value and the methods toBe and notToBe perform the comparisons. If conditions are not satisfied, they throw runtime errors. This class-based approach leverages C++'s support for OOP to provide a straightforward implementation.
Java
C#
Time Complexity: O(1) for both methods.
Space Complexity: O(1).
| Approach | Complexity |
|---|---|
| Closure-Based Approach | Time Complexity: O(1) for both |
| Class-Based Approach | Time Complexity: O(1) for both methods. |
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