CSS Selector Generator


65582.1.0a month ago4 years agoMinified + gzip package size for @medv/finder in KB




npm Build status npm bundle size

CSS Selector Generator


  • Generates shortest selectors
  • Unique selectors per page
  • Stable and robust selectors
  • 2.1 kB gzip and minify size


npm install @medv/finder

Finder can be used via modules:

<script type="module">
  import {finder} from 'https://medv.io/finder/finder.js'


import {finder} from '@medv/finder'

document.addEventListener('click', event => {
  const selector = finder(event.target)


Example of generated selector:

.blog > article:nth-child(3) .add-comment


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

Chrome Extension

Generate the unique selectors in your browser by using Chrome Extension



If you find any bugs or have a feature request, please open an issue on github!

The npm package download data comes from npm's download counts api and package details come from npms.io.