Benchmark: helpers.merge vs spread vs underscore.extend

HTML Preparation code:


<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js'></script>

Tests:

helpers.merge
var a = { a: 'oh', b: 'my' }; var b = { c: 'goddess' }; var merge = function (a, b, options) { if (options == null) { options = {}; } if (!a) { return b; } if (!b) { return a; } var deep = options.deep || false; var sum = options.sum || false; var r ={}; for(var i in a ){ r[i] = a[i]; } for(var j in b ){ if (deep && r.hasOwnProperty(j) && this.isObject(r[j]) && this.isObject(b[j])) { r[j] = this.merge(r[j], b[j], options); } else { if( sum === true ) { if( ( jpath.isNumber( r[ j ] ) === true ) && ( jpath.isNumber( b[ j ] ) === true ) ) { r[j] += b[j]; } else { r[j] = b[j]; } } else { r[j] = b[j]; } } } return r; }; var c = merge(a, b);
object.assign
var a = { a: 'oh', b: 'my' }; var b = { c: 'goddess' }; var c = { ...a, ...b}
underscore.extend
var a = { a: 'oh', b: 'my' }; var b = { c: 'goddess' }; var createAssigner = function(keysFunc, undefinedOnly) { return function(obj) { var length = arguments.length; if (length < 2 || obj == null) return obj; for (var index = 1; index < length; index++) { var source = arguments[index], keys = keysFunc(source), l = keys.length; for (var i = 0; i < l; i++) { var key = keys[i]; if (!undefinedOnly || obj[key] === void 0) obj[key] = source[key]; } } return obj; }; }; var allKeys = function(obj) { if (!_.isObject(obj)) return []; var keys = []; for (var key in obj) keys.push(key); return keys; }; var extend = createAssigner(allKeys); var c = extend(a, b);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
helpers.merge
object.assign
underscore.extend

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.88 Safari/537.36

Browser/OS: Chrome 87 on Linux

View result in a separate tab

Test name	Executions per second
helpers.merge	18600456.0 Ops/sec
object.assign	1844053.2 Ops/sec
underscore.extend	5216041.5 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 2 months ago):

LLMs can make mistakes. Check important info.

Measuring the performance of JavaScript merge functions is an interesting benchmark!

**Overview**

The provided JSON represents a microbenchmarking test suite, where three different approaches are compared:

1. `helpers.merge` (a custom implementation)
2. `object.assign` (a built-in JavaScript method)
3. `underscore.extend` (a library function)

Each approach has its pros and cons.

**`helpers.merge`**

This is the custom implementation provided in the benchmark definition. It's a recursive function that takes two objects, `a` and `b`, as input and returns their merged result. The function also accepts optional `options` object with two properties: `deep` and `sum`.

Pros:

* Customizable behavior through the `options` object
* Supports merging nested objects

Cons:

* More complex implementation compared to built-in methods
* May be slower due to recursive calls

**`object.assign`**

This is a built-in JavaScript method that returns a new object created by copying all enumerable own properties from one or more source objects.

Pros:

* Fast and lightweight implementation
* Built-in, so it's likely optimized for performance

Cons:

* Limited customization options
* Only merges top-level properties, not nested ones

**`underscore.extend`**

This is a library function provided by the Lodash utility library. It creates a new object with the properties of two source objects.

Pros:

* Fast and lightweight implementation
* Supports merging nested objects through optional `deep` parameter

Cons:

* External dependency on the Lodash library
* May be slower than built-in methods due to function call overhead

**Other considerations**

When choosing between these approaches, consider the following factors:

* Performance: If speed is critical, `object.assign` might be the best choice. For more complex merging scenarios or customization, `helpers.merge` might be a better fit.
* Customization: If you need fine-grained control over the merging process, `helpers.merge` offers the most flexibility.
* Library dependencies: If using Lodash library is acceptable, `underscore.extend` can provide a convenient and efficient solution.

**Alternatives**

If none of these approaches suit your needs, consider other merge functions or libraries:

1. `Array.prototype.reduce()`: Can be used for merging objects by reducing an array of property-value pairs.
2. `JSON.merge()`: An older ECMAScript method for merging JSON objects (not supported in modern browsers).
3. Other library functions, such as `merge` from the `deep-extend` or `extend` from the `fast-deep-equal` libraries.

Keep in mind that these alternatives might have varying degrees of complexity and performance characteristics compared to the original benchmark implementations.

Related benchmarks:

helpers.merge vs spread vs underscore.extend (version: 0)

Comparing performance of: helpers.merge vs object.assign vs underscore.extend

Created: 3 years ago by: Guest

Jump to the latest result

helpers.merge

object.assign

underscore.extend

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 2 months ago):