Benchmark Overview

The MeasureThat.net website allows users to create and run JavaScript microbenchmarks, including the provided benchmark: "JavaScript spread operator vs Object.assign performance GifCo". This benchmark compares the performance of two approaches to merge objects in JavaScript.

Options Compared

Two options are compared:

1. Using the spread operator: The ... operator is used to merge two objects into a new object. Specifically, the test creates two objects, firstObject and secondObject, and then uses the spread operator (...) to merge them into a single object, finalObject.
2. Using Object.assign(): The Object.assign() method is used to copy properties from one or more sources (in this case, secondObject) into a target object (firstObject).

Pros and Cons of Each Approach

1. Using the spread operator:
   • Pros:
     • Can be more concise and readable than using Object.assign()
     • Can handle nested objects and arrays
   • Cons:
     • May not be supported in older browsers or environments that don't support the ... operator
2. Using Object.assign():
   • Pros:
     • Widely supported across browsers and environments
     • Reliable way to merge objects, even with nested structures
   • Cons:
     • Can result in a more verbose code snippet

Library Used

None.

Special JS Feature or Syntax

The ... operator used in the spread operator approach is a new JavaScript feature introduced in ECMAScript 2018 (ES10). This allows for concise merging of objects and arrays. If your target environment doesn't support this feature, you may need to use an alternative approach or polyfill.

Benchmark Results

According to the latest benchmark results, Chrome 109 on Windows Desktop achieved:

• Using Object.assign(): 4,892,538 executions per second
• Using the spread operator: 1,764,053 executions per second

These results suggest that using Object.assign() is generally faster than the spread operator approach.

Alternative Approaches

Other ways to merge objects in JavaScript include:

• Using the merge function from a library like Lodash or Underscore.js
• Implementing your own merge function using conditional statements and array manipulation
• Using a template literal with nested properties (introduced in ECMAScript 2020)

Keep in mind that each approach has its pros and cons, and the best choice depends on your specific use case, target environment, and performance requirements.