/*
  Adapted from https://github.com/lydell/source-map-url
  Which carries the licensing:
    Copyright 2014 Simon Lydell
    X11 (“MIT”) Licensed.

  Forked here because that one doesn't anchor to the end of the file, and that's pretty important for us.
*/

const innerRegex = /[#@] sourceMappingURL=([^\s'"]*)/;
const regex = RegExp(
    "(?:" +
      "/\\*" +
      "(?:\\s*\r?\n(?://)?)?" +
      "(?:" + innerRegex.source + ")" +
      "\\s*" +
      "\\*/" +
      "|" +
      "//(?:" + innerRegex.source + ")" +
    ")" +
    "\\s*$"
  );

export function insertBefore(code: string, string: string) {
  let match = code.match(regex);
  if (match) {
    return code.slice(0, match.index) + string + code.slice(match.index);
  } else {
    return code + string;
  }
}