Function gobbleHex

src/utils.js:167–206

(str)

}

function gobbleHex(str) {
  const lower = str.toLowerCase();
  let hex = "";
  let spaceTerminated = false;

  // eslint-disable-next-line no-undefined
  for (let i = 0; i < 6 && lower[i] !== undefined; i++) {
    const code = lower.charCodeAt(i);
    // check to see if we are dealing with a valid hex char [a-f|0-9]
    const valid = (code >= 97 && code <= 102) || (code >= 48 && code <= 57);
    // https://drafts.csswg.org/css-syntax/#consume-escaped-code-point
    spaceTerminated = code === 32;

    if (!valid) {
      break;
    }

    hex += lower[i];
  }

  if (hex.length === 0) {
    // eslint-disable-next-line no-undefined
    return undefined;
  }

  const codePoint = parseInt(hex, 16);

  const isSurrogate = codePoint >= 0xd800 && codePoint <= 0xdfff;
  // Add special case for
  // "If this number is zero, or is for a surrogate, or is greater than the maximum allowed code point"
  // https://drafts.csswg.org/css-syntax/#maximum-allowed-code-point
  if (isSurrogate || codePoint === 0x0000 || codePoint > 0x10ffff) {
    return ["\uFFFD", hex.length + (spaceTerminated ? 1 : 0)];
  }

  return [
    String.fromCodePoint(codePoint),
    hex.length + (spaceTerminated ? 1 : 0),
  ];
}

const CONTAINS_ESCAPE = /\\/;