Function _ifThreeCodePointsWouldStartAnIdentSequence

lib/css/syntax.js:425–441

(input, pos, f, s, t)

 * @returns {boolean} true, if the three code points start an ident sequence
 */
const _ifThreeCodePointsWouldStartAnIdentSequence = (input, pos, f, s, t) => {
	const first = f || input.charCodeAt(pos - 1);
	const second = s || input.charCodeAt(pos);
	const third = t || input.charCodeAt(pos + 1);
	if (first === CC_HYPHEN_MINUS) {
		return (
			_isIdentStartCodePointCC(second) ||
			second === CC_HYPHEN_MINUS ||
			_ifTwoCodePointsAreValidEscape(input, pos, second, third)
		);
	}
	if (_isIdentStartCodePointCC(first)) return true;
	if (first === CC_REVERSE_SOLIDUS) {
		return _ifTwoCodePointsAreValidEscape(input, pos, first, second);
	}
	return false;
};

/**
 * Spec: "three code points would start a number".