site/node_modules/hast-util-parse-selector/lib/index.js

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2024-10-14 06:09:33 +00:00
/**
* @typedef {import('hast').Element} Element
* @typedef {import('hast').Properties} Properties
*/
/**
* @template {string} SimpleSelector
* Selector type.
* @template {string} DefaultTagName
* Default tag name.
* @typedef {(
* SimpleSelector extends ''
* ? DefaultTagName
* : SimpleSelector extends `${infer TagName}.${infer Rest}`
* ? ExtractTagName<TagName, DefaultTagName>
* : SimpleSelector extends `${infer TagName}#${infer Rest}`
* ? ExtractTagName<TagName, DefaultTagName>
* : SimpleSelector extends string
* ? SimpleSelector
* : DefaultTagName
* )} ExtractTagName
* Extract tag name from a simple selector.
*/
const search = /[#.]/g
/**
* Create a hast element from a simple CSS selector.
*
* @template {string} Selector
* Type of selector.
* @template {string} [DefaultTagName='div']
* Type of default tag name (default: `'div'`).
* @param {Selector | null | undefined} [selector]
* Simple CSS selector (optional).
*
* Can contain a tag name (`foo`), classes (`.bar`), and an ID (`#baz`).
* Multiple classes are allowed.
* Uses the last ID if multiple IDs are found.
* @param {DefaultTagName | null | undefined} [defaultTagName='div']
* Tag name to use if `selector` does not specify one (default: `'div'`).
* @returns {Element & {tagName: ExtractTagName<Selector, DefaultTagName>}}
* Built element.
*/
export function parseSelector(selector, defaultTagName) {
const value = selector || ''
/** @type {Properties} */
const props = {}
let start = 0
/** @type {string | undefined} */
let previous
/** @type {string | undefined} */
let tagName
while (start < value.length) {
search.lastIndex = start
const match = search.exec(value)
const subvalue = value.slice(start, match ? match.index : value.length)
if (subvalue) {
if (!previous) {
tagName = subvalue
} else if (previous === '#') {
props.id = subvalue
} else if (Array.isArray(props.className)) {
props.className.push(subvalue)
} else {
props.className = [subvalue]
}
start += subvalue.length
}
if (match) {
previous = match[0]
start++
}
}
return {
type: 'element',
// @ts-expect-error: tag name is parsed.
tagName: tagName || defaultTagName || 'div',
properties: props,
children: []
}
}