var objectsArray = Array(1000).fill(() => { const key = Math.random().toString(36).substring(2, 5); const value = Math.random().toString(36).substring(2, 5); return {[key]: value};});var combined = objectsArray.reduce((memo, obj) => ({memo, obj}), {});var combined = {}objectsArray.forEach(obj => { for (key in obj) { combined[key] = obj[key]; }});var combined = Object.assign(objectsArray)var combined = {}objectsArray.forEach(obj => Object.assign(combined, obj));var combined = objectsArray.reduce((memo, obj) => Object.assign(memo, obj), {});--enable-precise-memory-info flag.
| Test case name | Result |
|---|---|
| Reduce and Spread | |
| ForEach and Mutate (for .. in loop) | |
| Mutate with Object.assign | |
| Foreach and Mutate (Object.assign) | |
| Reduce Mutate |
| Test name | Executions per second |
|---|---|
| Reduce and Spread | 4155.5 Ops/sec |
| ForEach and Mutate (for .. in loop) | 1259.8 Ops/sec |
| Mutate with Object.assign | 15010.8 Ops/sec |
| Foreach and Mutate (Object.assign) | 7108.1 Ops/sec |
| Reduce Mutate | 6919.2 Ops/sec |
Let's dive into the world of JavaScript benchmarks.
The provided JSON represents a benchmark named "Reduce and Spread vs. Foreach and Mutate 2". This benchmark compares four different approaches to merge an array of objects:
for loop)Object.assignObject.assign)Now, let's break down each approach:
Reduce and Spread
This method uses the reduce() function to merge the objects in the array. The spread operator (...) is used to concatenate the properties of each object into a single object.
Pros: Efficient use of array methods and concise code. Cons: May have performance overhead due to the creation of intermediate objects.
ForEach and Mutate (using for loop)
This method uses a for loop to iterate over the array of objects. For each iteration, it uses the spread operator (...) to concatenate the properties of the current object with the result object.
Pros: Easy to understand and modify.
Cons: May have performance overhead due to the use of a for loop and explicit property concatenation.
Mutate with Object.assign
This method uses the Object.assign() function to merge the objects in the array. The first argument is the target object, which is initialized as an empty object.
Pros: Efficient use of built-in functions. Cons: May have performance overhead due to the creation of intermediate objects.
Foreach and Mutate (using Object.assign)
This method uses a for...of loop to iterate over the array of objects. For each iteration, it uses Object.assign() to merge the properties of the current object with the result object.
Pros: Efficient use of built-in functions. Cons: May have performance overhead due to the creation of intermediate objects.
Now, let's talk about the libraries used in this benchmark:
The only library mentioned is not explicitly stated, but it can be inferred that the benchmark uses the Array and Object prototypes, which are part of the JavaScript standard library.
Some special JS features used in this benchmark include:
...)=>)reduce(), forEach(), and assign()Other considerations:
Alternatives to these approaches include:
Array.prototype.reduce() method with a custom merge functionOverall, this benchmark provides a useful comparison of different approaches to merging arrays of objects in JavaScript. By analyzing the pros and cons of each approach, developers can choose the most efficient and readable solution for their specific use case.
