Function encodeString

src/string-util.ts:27–92

(str: string)

 * @returns {string}
 */
export function encodeString(str: string): string {
  const len = str.length;
  if (len === 0) {
    return '';
  }

  let out = '';
  let lastPos = 0;
  let i = 0;

  outer: for (; i < len; i++) {
    let c = str.charCodeAt(i);

    // ASCII
    while (c < 0x80) {
      if (noEscape[c] !== 1) {
        if (lastPos < i) out += str.slice(lastPos, i);
        lastPos = i + 1;
        out += hexTable[c];
      }

      if (++i === len) break outer;

      c = str.charCodeAt(i);
    }

    if (lastPos < i) out += str.slice(lastPos, i);

    // Multi-byte characters ...
    if (c < 0x800) {
      lastPos = i + 1;
      out += hexTable[0xc0 | (c >> 6)] + hexTable[0x80 | (c & 0x3f)];
      continue;
    }
    if (c < 0xd800 || c >= 0xe000) {
      lastPos = i + 1;
      out +=
        hexTable[0xe0 | (c >> 12)] +
        hexTable[0x80 | ((c >> 6) & 0x3f)] +
        hexTable[0x80 | (c & 0x3f)];
      continue;
    }
    // Surrogate pair
    ++i;

    // This branch should never happen because all URLSearchParams entries
    // should already be converted to USVString. But, included for
    // completion's sake anyway.
    if (i >= len) {
      throw new Error('URI malformed');
    }

    const c2 = str.charCodeAt(i) & 0x3ff;

    lastPos = i + 1;
    c = 0x10000 + (((c & 0x3ff) << 10) | c2);
    out +=
      hexTable[0xf0 | (c >> 18)] +