Benchmark: Object initialization direct vs. spread vs. Object.assign

Script Preparation code:

let props = [
  "astId",
  "astCode",
  "astDescription",
  "sttId",
  "sttValue",
  "sttDescription",
  "asttId",
  "asttDescription",
  "astpId",
  "astpCode",
  "astpDescription",
  "astpMake",
  "astpModel",
  "astSerialNumber",
  "astAcquiredOn",
  "astInstalledOn",
  "astWarrantyExpiresOn",
  "pltId",
  "astIdParent",
  "astCodeParent",
  "astDescriptionParent",
  "pltPlantCode",
  "pltDescription",
  "wrcId",
  "wrcShortDesc",
  "wrcDescription",
  "mcnCode",
  "mcnDescription",
  "mchtDescription",
  "astIdAstAv",
  "purchaser",
  "purchase Date",
];

let empty = {};
props.forEach(prop => empty[prop] = null);

function createEmptyRow() {
  const result = {};
  props.forEach(prop => result[prop] = null);
  return result;
}

function copyEmptyRow() {
  return { ...empty }
}

function copyEmptyRowAssign() {
  return Object.assign({}, empty);
}

Tests:

Direct
var data = createEmptyRow()
Spread
var data = copyEmptyRow()
Object.assign
var data = copyEmptyRowAssign()

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Direct
Spread
Object.assign

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:129.0) Gecko/20100101 Firefox/129.0

Browser/OS: Firefox 129 on Windows

View result in a separate tab

Test name	Executions per second
Direct	379109.8 Ops/sec
Spread	974225.7 Ops/sec
Object.assign	5191698.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the provided benchmark.

**Benchmark Overview**

The benchmark tests three different ways to create an empty object in JavaScript: directly using an empty object literal, using the spread operator (`...`), and using `Object.assign()`.

**Options Compared**

* **Directly using an empty object literal**: `let result = {};`
* **Using the spread operator (`...`)**: `{ ...empty }`
* **Using `Object.assign()`**: `Object.assign({}, empty)`

**Pros and Cons of Each Approach:**

1. **Directly using an empty object literal**:
	* Pros: Fast, simple, and concise.
	* Cons: May not work in older browsers that don't support object literals or the spread operator.
2. **Using the spread operator (`...`)**:
	* Pros: Fast, modern, and widely supported (including in Firefox 129).
	* Cons: Introduced with ECMAScript 2018, so may require transpilation for older browsers.
3. **Using `Object.assign()`**:
	* Pros: Works in all browsers that support JavaScript, including older ones.
	* Cons: Generally slower and more verbose than the other two options.

**Library Usage**

None of the benchmark test cases use any external libraries. The only library used is `props`, an array of property names used to create the empty object.

**Special JS Features or Syntax**

The benchmark uses the spread operator (`...`), which was introduced in ECMAScript 2018 (ES2018). It also uses `Object.assign()`, which has been a part of JavaScript since its inception. There are no special features or syntaxes used beyond these two.

**Other Alternatives**

In addition to the three options compared, there is another way to create an empty object using the bitwise NOT operator (`!`) with the `Object` constructor:

* `let result = new Object(!);`

This method creates a new, empty object by negating the zero value of the Boolean type, which is 0. However, this approach is generally considered less readable and less reliable than the other three options.

In summary, the benchmark compares the performance of three ways to create an empty object in JavaScript: directly using an object literal, using the spread operator, and using `Object.assign()`. The results show that all three approaches are fast and widely supported, but `Object.assign()` is generally slower.

Related benchmarks:

Object initialization direct vs. spread vs. Object.assign (version: 0)

Comparing performance of: Direct vs Spread vs Object.assign

Created: one year ago by: Guest

Jump to the latest result

Direct

Spread

Object.assign

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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