mostly-dom/src/hyperscript/parseSelector.ts

A virtual-dom for TypeScript

const classIdSplit = /([\.#]?[a-zA-Z0-9\u007F-\uFFFF_:-]+)/

export function parseSelector(selector: string) {
  let tagName: string | void
  let id = ''
  const classes: Array<string> = []

  const tagParts = selector.split(classIdSplit)

  let part: string | void
  let type

  for (let i = 0; i < tagParts.length; i++) {
    part = tagParts[i]

    if (!part)
      continue

    type = part.charAt(0)

    if (!tagName) {
      tagName = part
    } else if (type === '.') {
      classes.push(part.substring(1, part.length))
    } else if (type === '#') {
      id = part.substring(1, part.length)
    }
  }

  return {
    tagName: tagName as string,
    id,
    className: classes.join(' '),
  }
}