JarCasting
finder
CSS Selector Generator
Features
- Generates shortest selectors
- Unique selectors per page
- Stable and robust selectors
- 2.1 kB gzip and minify size
Install
npm install @medv/finder
Finder can be used via modules:
<script type="module">
import {finder} from 'https://medv.io/finder/finder.js'
</script>
Usage
import {finder} from '@medv/finder'
document.addEventListener('click', event => {
const selector = finder(event.target)
console.log(selector)
})
Example
Example of generated selector:
.blog > article:nth-child(3) .add-comment
Configuration
finder takes configuration object as second parameters. Here is example of all params with default values:
const selector = finder(event.target, {
root: document.body,
className: (name) => true,
tagName: (name) => true,
attr: (name, value) => false,
seedMinLength: 1,
optimizedMinLength: 2,
threshold: 1000,
maxNumberOfTries: 10_000,
})
root: Element
Root of search, defaults to document.body.
idName: (name: string) => boolean
Check if this ID can be used. For example you can restrict using framework specific IDs:
const selector = finder(event.target, {
idName: name => !name.startsWith('ember')
})
className: (name: string) => boolean
Check if this class name can be used. For example you can restrict using is-* class names:
const selector = finder(event.target, {
className: name => !name.startsWith('is-')
})
tagName: (name: string) => boolean
Check if tag name can be used, same as className.
attr: (name: string, value: string) => boolean
Check if attr name can be used.
seedMinLength: number
Minimum length of levels in fining selector. Starts from 1. For more robust selectors give this param value around 4-5 depending on depth of you DOM tree. If finder hits root this param is ignored.
optimizedMinLength: number
Minimum length for optimising selector. Starts from 2. For example selector body > div > div > p can be optimized to body p.
threshold: number
Max number of selectors to check before falling into nth-child usage. Checking for uniqueness of selector is very costs operation, if you have DOM tree depth of 5, with 5 classes on each level, that gives you more than 3k selectors to check. finder uses two step approach so it's reaching this threshold in some cases twice. Default 1000 is good enough in most cases.
maxNumberOfTries: number
Max number of tries when we do the optimization. It is a trade-off between optimization and efficiency. Default 10_000 is good enough in most cases.
Google Chrome Extension
Generate the unique selectors in your browser by using Chrome Extension