Benchmark Overview

The provided JSON represents a JavaScript benchmark test case on MeasureThat.net. The goal of this benchmark is to compare the performance of different approaches for deleting a property from an object in JavaScript.

Script Preparation Code

The script preparation code defines an object obj with two properties, "one" and "two", both initialized as null.

var obj = {
    "one": null,
    "two": null
}

This setup is used as a common base for all test cases.

Test Cases

There are four individual test cases:

1. Delete Existing, No Check

delete obj["two"]

This test case deletes the "two" property from the obj object without performing any existence checks.

2. Delete Existing, Check

if (obj["two"] !== undefined) {
    delete obj["two"]
}

This test case first checks if the "two" property exists in the obj object and only then deletes it.

3. Delete Nonexisting, No Check

delete obj["three"]

This test case attempts to delete a non-existent property "three" from the obj object without performing any existence checks.

4. Delete Nonexisting, Check

if (obj["two"] !== undefined) {
    delete obj["three"]
}

This test case first checks if the "two" property exists in the obj object and only then attempts to delete a non-existent property "three".

Library: None

There are no external libraries used in these benchmark test cases.

Special JS Feature/Syntax: None

None of the provided test cases utilize any special JavaScript features or syntax, such as async/await, Promises, or modern ES6+ features.

Performance Comparison

The benchmark tests the performance of deleting a property from an object using two approaches:

1. Direct Deletion: Deleting the property directly without existence checks (Test Case 1 and 3).
2. Existence Check: Performing an existence check before deletion (Test Cases 2 and 4).

The results show that direct deletion without existence checks is generally faster than performing an existence check.

Pros and Cons

• Direct Deletion:
  • Pros: Faster performance, as it avoids the overhead of an existence check.
  • Cons: May cause errors if the property does not exist.
• Existence Check:
  • Pros: Prevents errors by checking for the existence of the property before deletion.
  • Cons: Slower performance due to the additional overhead of the existence check.

Alternatives

Other approaches for deleting a property from an object in JavaScript include:

1. Using in operator to check for property existence, e.g., if ("two" in obj) { delete obj["two"] }.
2. Using hasOwnProperty() method on the prototype chain, e.g., if (obj.hasOwnProperty("two")) { delete obj["two"] }.
3. Using Object.prototype.hasOwnProperty.call() to check for property existence, e.g., if (Object.prototype.hasOwnProperty.call(obj, "two")) { delete obj["two"] }.

However, these alternatives may not provide the same performance benefits as direct deletion without existence checks.