@jsenv/href/src/hrefToOrigin/hrefToOrigin.js

url helpers not relying on URL constructor

import { hrefToScheme } from "../hrefToScheme/hrefToScheme.js"

export const hrefToOrigin = (href) => {
  const scheme = hrefToScheme(href)

  if (scheme === "file") {
    return "file://"
  }

  if (scheme === "http" || scheme === "https") {
    const secondProtocolSlashIndex = scheme.length + "://".length
    const pathnameSlashIndex = href.indexOf("/", secondProtocolSlashIndex)

    if (pathnameSlashIndex === -1) return href
    return href.slice(0, pathnameSlashIndex)
  }

  return href.slice(0, scheme.length + 1)
}