index.js

/**
 * @module  color-stringify
 */

import names from 'color-name';

export default stringify;

/** Inverted color names */
var nameValues = {};
for (var name in names) {
	nameValues[names[name]] = name;
}


/**
 * Stringify color values to any target format
 *
 * @param {array} values An array of values to stringify, by default - rgb[a]
 * @param {string} type A color space to stringify values to. By default - rgb.
 */
function stringify (values, type) {
	// Accept object from `color-parse`
	if (!Array.isArray(values) && values.values) {
		var color = values
		if (color.alpha === 1 || color.alpha === undefined) {
			return stringify(color.values, type || color.space)
		} else {
			var values = color.values.slice()
			values.push(color.alpha)
			return stringify(values, type || color.space)
		}
	}

	if (type === 'hex') {
		var res = values.slice(0,3).map(function (value) {
			value = Math.round(value);
			return (value < 16 ? '0' : '') + value.toString(16);
		}).join('');

		if (res[0] === res[1] && res[2] === res[3] && res[4] === res[5]) res = res[0] + res[2] + res[4];

		return '#' + res;
	}

	if (type === 'keyword') {
		return nameValues[values];
	}

	if (type === 'adobe1') {
		return 'R:' + values[0] + ', G:' + values[1] + ', B:' + values[2];
	}

	if (type === 'adobe2') {
		return '(R' + values[0] + ' / G' + values[1] + ' / B' + values[2] + ')';
	}

	var isPercent, isAlphaSpace;

	//convert rgb to percents
	if (type === 'percent') {
		type = 'rgb';
		values = values.map(function (value, i) {
			if (i === 3) return value;
			return Math.round(value * 100 / 255);
		});

		isPercent = true;
		isAlphaSpace = true;
	}

	type = type || 'rgb';

	//catch hwb/hsl/hsv
	isPercent = isPercent ? isPercent : type[0] === 'h';

	//detect whether alpha-perfix is needed
	isAlphaSpace = isAlphaSpace || /rgb|hs[lv]/i.test(type);

	//normalize space name
	if (isAlphaSpace && type[type.length - 1] === 'a') {
		type = type.slice(0,-1);
	}

	//normalize alpha
	var alpha = 1;
	if (values.length > type.length) {
		alpha = values.pop();
	}

	//decide the space name
	var alphaPf = isAlphaSpace && alpha < 1 ? 'a' : '';

	//<hue> case requires percents
	var res = type + alphaPf;

	res += '(' + values.map(function (value, i) {
		if (isPercent && !(type[i] === 'h')) {
			return value + '%';
		}
		else {
			return value;
		}
	}).join(', ');

	res += ( alpha < 1 ? ', ' + alpha : '' ) + ')';

	return res;
}