46 lines
1.4 KiB
JavaScript
46 lines
1.4 KiB
JavaScript
const hexCharacters = 'a-f\\d';
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const match3or4Hex = `#?[${hexCharacters}]{3}[${hexCharacters}]?`;
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const match6or8Hex = `#?[${hexCharacters}]{6}([${hexCharacters}]{2})?`;
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const nonHexChars = new RegExp(`[^#${hexCharacters}]`, 'gi');
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const validHexSize = new RegExp(`^${match3or4Hex}$|^${match6or8Hex}$`, 'i');
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export default function hexRgb(hex, options = {}) {
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if (typeof hex !== 'string' || nonHexChars.test(hex) || !validHexSize.test(hex)) {
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throw new TypeError('Expected a valid hex string');
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}
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hex = hex.replace(/^#/, '');
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let alphaFromHex = 1;
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if (hex.length === 8) {
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alphaFromHex = Number.parseInt(hex.slice(6, 8), 16) / 255;
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hex = hex.slice(0, 6);
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}
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if (hex.length === 4) {
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alphaFromHex = Number.parseInt(hex.slice(3, 4).repeat(2), 16) / 255;
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hex = hex.slice(0, 3);
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}
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if (hex.length === 3) {
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hex = hex[0] + hex[0] + hex[1] + hex[1] + hex[2] + hex[2];
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}
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const number = Number.parseInt(hex, 16);
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const red = number >> 16;
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const green = (number >> 8) & 255;
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const blue = number & 255;
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const alpha = typeof options.alpha === 'number' ? options.alpha : alphaFromHex;
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if (options.format === 'array') {
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return [red, green, blue, alpha];
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}
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if (options.format === 'css') {
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const alphaString = alpha === 1 ? '' : ` / ${Number((alpha * 100).toFixed(2))}%`;
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return `rgb(${red} ${green} ${blue}${alphaString})`;
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}
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return {red, green, blue, alpha};
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}
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