Function encode

lib/punycode.js:302–388

(input)

 * @returns {String} The resulting Punycode string of ASCII-only symbols.
 */
const encode = function(input) {
	const output = [];

	// Convert the input in UCS-2 to an array of Unicode code points.
	input = ucs2decode(input);

	// Cache the length.
	const inputLength = input.length;

	// Initialize the state.
	let n = initialN;
	let delta = 0;
	let bias = initialBias;

	// Handle the basic code points.
	for (const currentValue of input) {
		if (currentValue < 0x80) {
			output.push(stringFromCharCode(currentValue));
		}
	}

	const basicLength = output.length;
	let handledCPCount = basicLength;

	// `handledCPCount` is the number of code points that have been handled;
	// `basicLength` is the number of basic code points.

	// Finish the basic string with a delimiter unless it's empty.
	if (basicLength) {
		output.push(delimiter);
	}

	// Main encoding loop:
	while (handledCPCount < inputLength) {

		// All non-basic code points < n have been handled already. Find the next
		// larger one:
		let m = maxInt;
		for (const currentValue of input) {
			if (currentValue >= n && currentValue < m) {
				m = currentValue;
			}
		}

		// Increase `delta` enough to advance the decoder's <n,i> state to <m,0>,
		// but guard against overflow.
		const handledCPCountPlusOne = handledCPCount + 1;
		if (m - n > floor((maxInt - delta) / handledCPCountPlusOne)) {
			error('overflow');
		}

		delta += (m - n) * handledCPCountPlusOne;
		n = m;

		for (const currentValue of input) {
			if (currentValue < n && ++delta > maxInt) {
				error('overflow');
			}