index.js

// eslint-disable-next-line unicorn/import-style
import chalk, {chalkStderr} from 'chalk';

const TEMPLATE_REGEX = /(?:\\(u(?:[a-f\d]{4}|{[a-f\d]{1,6}})|x[a-f\d]{2}|.))|(?:{(~)?(#?[\w:]+(?:\([^)]*\))?(?:\.#?[\w:]+(?:\([^)]*\))?)*)(?:[ \t]|(?=\r?\n)))|(})|((?:.|[\r\n\f])+?)/gi;
const STYLE_REGEX = /(?:^|\.)(?:(?:(\w+)(?:\(([^)]*)\))?)|(?:#(?=[:a-fA-F\d]{2,})([a-fA-F\d]{6})?(?::([a-fA-F\d]{6}))?))/g;
const STRING_REGEX = /^(['"])((?:\\.|(?!\1)[^\\])*)\1$/;
const ESCAPE_REGEX = /\\(u(?:[a-f\d]{4}|{[a-f\d]{1,6}})|x[a-f\d]{2}|.)|([^\\])/gi;

const ESCAPES = new Map([
	['n', '\n'],
	['r', '\r'],
	['t', '\t'],
	['b', '\b'],
	['f', '\f'],
	['v', '\v'],
	['0', '\0'],
	['\\', '\\'],
	['e', '\u001B'],
	['a', '\u0007'],
]);

function unescape(c) {
	const u = c[0] === 'u';
	const bracket = c[1] === '{';

	if ((u && !bracket && c.length === 5) || (c[0] === 'x' && c.length === 3)) {
		return String.fromCodePoint(Number.parseInt(c.slice(1), 16));
	}

	if (u && bracket) {
		return String.fromCodePoint(Number.parseInt(c.slice(2, -1), 16));
	}

	return ESCAPES.get(c) || c;
}

function parseArguments(name, arguments_) {
	const results = [];
	const chunks = arguments_.trim().split(/\s*,\s*/g);
	let matches;

	for (const chunk of chunks) {
		const number = Number(chunk);
		if (!Number.isNaN(number)) {
			results.push(number);
		} else if ((matches = chunk.match(STRING_REGEX))) {
			results.push(matches[2].replace(ESCAPE_REGEX, (_, escape, character) => escape ? unescape(escape) : character));
		} else {
			throw new Error(`Invalid Chalk template style argument: ${chunk} (in style '${name}')`);
		}
	}

	return results;
}

function parseHex(hex) {
	const n = Number.parseInt(hex, 16);
	return [
		// eslint-disable-next-line no-bitwise
		(n >> 16) & 0xFF,
		// eslint-disable-next-line no-bitwise
		(n >> 8) & 0xFF,
		// eslint-disable-next-line no-bitwise
		n & 0xFF,
	];
}

function parseStyle(style) {
	STYLE_REGEX.lastIndex = 0;

	const results = [];
	let matches;

	while ((matches = STYLE_REGEX.exec(style)) !== null) {
		const name = matches[1];

		if (matches[2]) {
			results.push([name, ...parseArguments(name, matches[2])]);
		} else if (matches[3] || matches[4]) {
			if (matches[3]) {
				results.push(['rgb', ...parseHex(matches[3])]);
			}

			if (matches[4]) {
				results.push(['bgRgb', ...parseHex(matches[4])]);
			}
		} else {
			results.push([name]);
		}
	}

	return results;
}

export function makeTemplate(chalk) {
	function buildStyle(styles) {
		const enabled = {};

		for (const layer of styles) {
			for (const style of layer.styles) {
				enabled[style[0]] = layer.inverse ? null : style.slice(1);
			}
		}

		let current = chalk;
		for (const [styleName, styles] of Object.entries(enabled)) {
			if (!Array.isArray(styles)) {
				continue;
			}

			if (!(styleName in current)) {
				throw new Error(`Unknown Chalk style: ${styleName}`);
			}

			current = styles.length > 0 ? current[styleName](...styles) : current[styleName];
		}

		return current;
	}

	function template(string) {
		const styles = [];
		const chunks = [];
		let chunk = [];

		// eslint-disable-next-line max-params
		string.replace(TEMPLATE_REGEX, (_, escapeCharacter, inverse, style, close, character) => {
			if (escapeCharacter) {
				chunk.push(unescape(escapeCharacter));
			} else if (style) {
				const string = chunk.join('');
				chunk = [];
				chunks.push(styles.length === 0 ? string : buildStyle(styles)(string));
				styles.push({inverse, styles: parseStyle(style)});
			} else if (close) {
				if (styles.length === 0) {
					throw new Error('Found extraneous } in Chalk template literal');
				}

				chunks.push(buildStyle(styles)(chunk.join('')));
				chunk = [];
				styles.pop();
			} else {
				chunk.push(character);
			}
		});

		chunks.push(chunk.join(''));

		if (styles.length > 0) {
			throw new Error(`Chalk template literal is missing ${styles.length} closing bracket${styles.length === 1 ? '' : 's'} (\`}\`)`);
		}

		return chunks.join('');
	}

	return template;
}

function makeChalkTemplate(template) {
	function chalkTemplate(firstString, ...arguments_) {
		if (!Array.isArray(firstString) || !Array.isArray(firstString.raw)) {
			// If chalkTemplate() was called by itself or with a string
			throw new TypeError('A tagged template literal must be provided');
		}

		const parts = [firstString.raw[0]];

		for (let index = 1; index < firstString.raw.length; index++) {
			parts.push(
				String(arguments_[index - 1]).replace(/[{}\\]/g, '\\$&'),
				String(firstString.raw[index]),
			);
		}

		return template(parts.join(''));
	}

	return chalkTemplate;
}

export const makeTaggedTemplate = chalkInstance => makeChalkTemplate(makeTemplate(chalkInstance));

export const template = makeTemplate(chalk);
export default makeChalkTemplate(template);

export const templateStderr = makeTemplate(chalkStderr);
export const chalkTemplateStderr = makeChalkTemplate(templateStderr);