hex-to-css-filter/dist/es2015/hex-to-css-filter.js

hex-to-css-filter - Easy way to generate colors from HEX to CSS Filters

import { Solver } from './solver';
import { Color } from './color';
/**
 * Transform a CSS Color from Hexadecimal to RGB color
 *
 * @param {string} hex hexadecimal color
 * @returns {([number, number, number] | [])} array with the RGB colors or empty array
 */
const hexToRgb = (hex) => {
    if (hex.length === 4) {
        return [parseInt(`0x${hex[1]}${hex[1]}`), parseInt(`0x${hex[2]}${hex[2]}`), parseInt(`0x${hex[3]}${hex[3]}`)];
    }
    if (hex.length === 7) {
        return [parseInt(`0x${hex[1]}${hex[2]}`), parseInt(`0x${hex[3]}${hex[4]}`), parseInt(`0x${hex[5]}${hex[6]}`)];
    }
    return [];
};
const isNumeric = (n) => !isNaN(parseFloat(n)) && isFinite(n);
// Memory cache for the computed results to avoid multiple
// calculations for the same color
let results = {};
/**
 * A function that transforms a HEX color into CSS filters
 *
 * @param colorValue string hexadecimal color
 * @param opts HexToCssConfiguration function configuration
 *
 */
export const hexToCSSFilter = (colorValue, opts = {}) => {
    let red;
    let green;
    let blue;
    if (results[colorValue] && !opts.forceFilterRecalculation) {
        return Object.assign({}, results[colorValue], { cache: true });
    }
    let color;
    try {
        [red, green, blue] = hexToRgb(colorValue);
        if (!isNumeric(red) || !isNumeric(green) || !isNumeric(blue)) {
            throw new Error(`hextToRgb returned an invalid value for '${colorValue}'`);
        }
        color = new Color(Number(red), Number(green), Number(blue));
    }
    catch (error) {
        throw new Error(`Color value should be in HEX format. ${error}`);
    }
    const solver = new Solver(color, Object.assign({}, 
    // `HexToCssConfiguration` Defaults
    {
        acceptanceLossPercentage: 5,
        maxChecks: 30,
        forceFilterRecalculation: false,
    }, opts));
    return (results[colorValue] = Object.assign({}, solver.solve(), {
        hex: colorValue,
        rgb: [red, green, blue],
        cache: false,
    }));
};
/**
 * A function that clears cached results
 *
 * @param  {string} key? HEX string value passed previously `#24639C`. If not passed, it clears all cached results
 * @returns void
 */
export const clearCache = (key) => {
    if (!key) {
        results = {};
    }
    else if (results[key]) {
        delete results[key];
    }
};