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https://github.com/justjavac/json-perf-loader
A loader for webpack to load JSON with performance advice
https://github.com/justjavac/json-perf-loader
fast fastify json performance performance-test webpack webpack-loader
Last synced: 30 days ago
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A loader for webpack to load JSON with performance advice
- Host: GitHub
- URL: https://github.com/justjavac/json-perf-loader
- Owner: justjavac
- License: mit
- Created: 2019-07-12T12:35:28.000Z (over 5 years ago)
- Default Branch: master
- Last Pushed: 2024-11-19T00:25:43.000Z (2 months ago)
- Last Synced: 2024-12-27T05:06:13.752Z (about 1 month ago)
- Topics: fast, fastify, json, performance, performance-test, webpack, webpack-loader
- Language: JavaScript
- Homepage:
- Size: 914 KB
- Stars: 19
- Watchers: 4
- Forks: 6
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
Awesome Lists containing this project
README
# json-perf-loader
[![cover][cover]][cover-url]
[![npm][npm]][npm-url]
[![download][download]][download-url]
A loader for webpack to load JSON with performance advice.
## The cost of parsing JSON
See [The cost of parsing JSON - V8](https://v8.dev/blog/cost-of-javascript-2019#json)
> Because the JSON grammar is much simpler than JavaScript’s grammar, JSON can be parsed more efficiently than JavaScript.
> This knowledge can be applied to improve start-up performance for web apps that ship large JSON-like configuration object literals (such as inline Redux stores).
> Instead of inlining the data as a JavaScript object literal.
>
> As long as the JSON string is only evaluated once, the `JSON.parse` approach is much faster compared to the JavaScript object literal, especially for cold loads.
> A good rule of thumb is to apply this technique for objects of **10 kB or larger** — but as always with performance advice, measure the actual impact before making any changes.
## Getting Started
To begin, you'll need to install `json-perf-loader`:
```shell
$ npm install json-perf-loader --save-dev
```
`json-perf-loader` works like
[`json-loader`](https://github.com/justjavac/json-loader), but much faster.
**index.js**
```js
import json from './file.json'
```
**webpack.config.js**
```js
module.exports = {
module: {
rules: [
{
test: /\.json$/i,
type: 'javascript/auto',
use: [
{
loader: 'json-perf-loader',
options: {
limit: 4096,
},
},
],
},
],
},
}
```
And run `webpack` via your preferred method.
**Note: `type: "javascript/auto"` is require**. See https://webpack.js.org/configuration/module/#ruletype
> `Rule.type` sets the type for a matching module.
> This prevents defaultRules and their default importing behaviors from occurring.
> For example, if you want to load a `.json` file through a custom loader, you'd need to set the `type` to `javascript/auto` to bypass webpack's built-in json importing.
## Options
### `limit`
Type: `Number|String`
Default: `1024 * 10`
The limit can be specified via loader options and defaults to `1024 * 10`. This is the recommended value for the V8 team.
#### `Number`
A `Number` specifying the maximum size of a file in bytes. If the file size is
**equal** or **greater** than the limit `JSON.parse` will be used.
**webpack.config.js**
```js
module.exports = {
module: {
rules: [
{
test: /\.json$/i,
type: 'javascript/auto',
use: [
{
loader: 'json-perf-loader',
options: {
limit: 10,
},
},
],
},
],
},
}
```
## License
[MIT](./LICENSE)
[npm]: https://img.shields.io/npm/v/json-perf-loader.svg
[npm-url]: https://npmjs.com/package/json-perf-loader
[download]: https://img.shields.io/npm/dm/json-perf-loader.svg?style=flat
[download-url]: https://npmcharts.com/compare/json-perf-loader?minimal=true
[tests]: https://dev.azure.com/justjavac/json-perf-loader/_apis/build/status/justjavac.json-perf-loader?branchName=master
[tests-url]: https://dev.azure.com/justjavac/json-perf-loader/_build/latest?definitionId=2&branchName=master
[cover]: https://codecov.io/gh/justjavac/json-perf-loader/branch/master/graph/badge.svg
[cover-url]: https://codecov.io/gh/justjavac/json-perf-loader