接受字符串的简写版本:

function rgbToHex（a）{ a=a.replace（/[^\d，]/g，“”）.split（“，”）; return“#”+（（1<<24）+（+a[0]<<16）+（+a[1]<<8）+ +a[2]）.toString（16）.slice（1） } document.write（rgbToHex（“rgb（255，255，255）”））;

来检查它是否已经是十六进制

function rgbToHex（a）{ if（~a.indexOf（“#”））返回 a; a=a.replace（/[^\d，]/g，“”）.split（“，”）; return“#”+（（1<<24）+（+a[0]<<16）+（+a[1]<<8）+ +a[2]）.toString（16）.slice（1） } document.write（“rgb： ”+rgbToHex（“rgb（255，255，255）”）+ “ -- hex： ”+rgbToHex（“#e2e2e2”））;

我遇到了这个问题，因为我想要解析任何颜色字符串值，并能够指定不透明度，所以我写了这个使用canvas API的函数。

var toRGBA = function () {
  var canvas = document.createElement('canvas');
  var context = canvas.getContext('2d');

  canvas.width = 1;
  canvas.height = 1;

  return function (color) {
    context.fillStyle = color;
    context.fillRect(0, 0, 1, 1);

    var data = context.getImageData(0, 0, 1, 1).data;

    return {
      r: data[0],
      g: data[1],
      b: data[2],
      a: data[3]
    };
  };
}();

关于context.fillStyle注意:

如果解析值导致失败，则必须忽略该值，属性必须保留其先前的值。

下面是一个你可以用来测试输入的Stack Snippet演示:

var toRGBA = function () { var canvas = document.createElement('canvas'); var context = canvas.getContext('2d'); canvas.width = 1; canvas.height = 1; return function (color) { context.fillStyle = color; context.fillRect(0, 0, 1, 1); var data = context.getImageData(0, 0, 1, 1).data; return { r: data[0], g: data[1], b: data[2], a: data[3] }; }; }(); var inputs = document.getElementsByTagName('input'); function setColor() { inputs[1].value = JSON.stringify(toRGBA(inputs[0].value)); document.body.style.backgroundColor = inputs[0].value; } inputs[0].addEventListener('input', setColor); setColor(); input { width: 200px; margin: 0.5rem; } <input value="cyan" /> <input readonly="readonly" />

我发现了这个，因为我认为它非常直截了当，有验证测试和支持alpha值(可选)，这将适合这种情况。

只要注释掉regex行，如果你知道你在做什么，它会快一点。

function hexToRGBA(hex, alpha){
    hex = (""+hex).trim().replace(/#/g,""); //trim and remove any leading # if there (supports number values as well)
    if (!/^(?:[0-9a-fA-F]{3}){1,2}$/.test(hex)) throw ("not a valid hex string"); //Regex Validator
    if (hex.length==3){hex=hex[0]+hex[0]+hex[1]+hex[1]+hex[2]+hex[2]} //support short form
    var b_int = parseInt(hex, 16);
    return "rgba("+[
        (b_int >> 16) & 255, //R
        (b_int >> 8) & 255, //G
        b_int & 255, //B
        alpha || 1  //add alpha if is set
    ].join(",")+")";
}

HEX转RGB (ES6) +测试[2022]

convertHexToRgb.ts:

/**
 * RGB color regexp
 */
export const RGB_REG_EXP = /rgb\((\d{1,3}), (\d{1,3}), (\d{1,3})\)/;

/**
 * HEX color regexp
 */
export const HEX_REG_EXP = /^#?(([\da-f]){3}|([\da-f]){6})$/i;

/**
 * Converts HEX to RGB.
 *
 * Color must be only HEX string and must be:
 *  - 7-characters starts with "#" symbol ('#ffffff')
 *  - or 6-characters without "#" symbol ('ffffff')
 *  - or 4-characters starts with "#" symbol ('#fff')
 *  - or 3-characters without "#" symbol ('fff')
 *
 * @function { color: string => string } convertHexToRgb
 * @return { string } returns RGB color string or empty string
 */
export const convertHexToRgb = (color: string): string => {
    const errMessage = `
    Something went wrong while working with colors...
    
    Make sure the colors provided to the "PieDonutChart" meet the following requirements:
    
    Color must be only HEX string and must be 
    7-characters starts with "#" symbol ('#ffffff')
    or 6-characters without "#" symbol ('ffffff')
    or 4-characters starts with "#" symbol ('#fff')
    or 3-characters without "#" symbol ('fff')
    
    - - - - - - - - -
    
    Error in: "convertHexToRgb" function
    Received value: ${color}
  `;

    if (
        !color
        || typeof color !== 'string'
        || color.length < 3
        || color.length > 7
    ) {
        console.error(errMessage);
        return '';
    }

    const replacer = (...args: string[]) => {
        const [
            _,
            r,
            g,
            b,
        ] = args;

        return '' + r + r + g + g + b + b;
    };

    const rgbHexArr = color
        ?.replace(HEX_REG_EXP, replacer)
        .match(/.{2}/g)
        ?.map(x => parseInt(x, 16));

    /**
     * "HEX_REG_EXP.test" is here to create more strong tests
     */
    if (rgbHexArr && Array.isArray(rgbHexArr) && HEX_REG_EXP.test(color)) {
        return `rgb(${rgbHexArr[0]}, ${rgbHexArr[1]}, ${rgbHexArr[2]})`;
    }

    console.error(errMessage);
    return '';
};

我正在使用Jest进行测试

color.spec.ts

describe('function "convertHexToRgb"', () => {
    it('returns a valid RGB with the provided 3-digit HEX color: [color = \'fff\']', () => {
        expect.assertions(2);

        const { consoleErrorMocked }  = mockConsole();
        const rgb = convertHexToRgb('fff');

        expect(RGB_REG_EXP.test(rgb)).toBeTruthy();
        expect(consoleErrorMocked).not.toHaveBeenCalled();
    });

    it('returns a valid RGB with the provided 3-digit HEX color with hash symbol: [color = \'#fff\']', () => {
        expect.assertions(2);

        const { consoleErrorMocked }  = mockConsole();
        const rgb = convertHexToRgb('#fff');

        expect(RGB_REG_EXP.test(rgb)).toBeTruthy();
        expect(consoleErrorMocked).not.toHaveBeenCalled();
    });

    it('returns a valid RGB with the provided 6-digit HEX color: [color = \'ffffff\']', () => {
        expect.assertions(2);

        const { consoleErrorMocked }  = mockConsole();
        const rgb = convertHexToRgb('ffffff');

        expect(RGB_REG_EXP.test(rgb)).toBeTruthy();
        expect(consoleErrorMocked).not.toHaveBeenCalled();
    });

    it('returns a valid RGB with the provided 6-digit HEX color with the hash symbol: [color = \'#ffffff\']', () => {
        expect.assertions(2);

        const { consoleErrorMocked }  = mockConsole();
        const rgb = convertHexToRgb(TEST_COLOR);

        expect(RGB_REG_EXP.test(rgb)).toBeTruthy();
        expect(consoleErrorMocked).not.toHaveBeenCalled();
    });

    it('returns an empty string when the provided value is not a string: [color = 1234]', () => {
        expect.assertions(2);

        const { consoleErrorMocked }  = mockConsole();

        // @ts-ignore
        const rgb = convertHexToRgb(1234);

        expect(rgb).toBe('');
        expect(consoleErrorMocked).toHaveBeenCalledTimes(1);
    });

    it('returns an empty string when the provided color is too short: [color = \'FF\']', () => {
        expect.assertions(2);

        const { consoleErrorMocked }  = mockConsole();

        const rgb = convertHexToRgb('FF');

        expect(rgb).toBe('');
        expect(consoleErrorMocked).toHaveBeenCalledTimes(1);
    });

    it('returns an empty string when the provided color is too long: [color = \'#fffffff\']', () => {
        expect.assertions(2);

        const { consoleErrorMocked }  = mockConsole();

        const rgb = convertHexToRgb('#fffffff');

        expect(rgb).toBe('');
        expect(consoleErrorMocked).toHaveBeenCalledTimes(1);
    });

    it('returns an empty string when the provided value is looks like HEX color string but has invalid symbols: [color = \'#fffffp\']', () => {
        expect.assertions(2);

        const { consoleErrorMocked }  = mockConsole();
        const rgb = convertHexToRgb('#fffffp');

        expect(rgb).toBe('');
        expect(consoleErrorMocked).toHaveBeenCalledTimes(1);
    });

    it('returns an empty string when the provided value is invalid: [color = \'*\']', () => {
        expect.assertions(2);

        const { consoleErrorMocked }  = mockConsole();

        const rgb = convertHexToRgb('*');

        expect(rgb).toBe('');
        expect(consoleErrorMocked).toHaveBeenCalledTimes(1);
    });

    it('returns an empty string when the provided value is undefined: [color = undefined]', () => {
        expect.assertions(2);

        const { consoleErrorMocked }  = mockConsole();

        // @ts-ignore
        const rgb = convertHexToRgb(undefined);

        expect(rgb).toBe('');
        expect(consoleErrorMocked).toHaveBeenCalledTimes(1);
    });
});

测试结果:

function "convertHexToRgb"
    √ returns a valid RGB with the provided 3-digit HEX color: [color = 'fff']
    √ returns a valid RGB with the provided 3-digit HEX color with hash symbol: [color = '#fff']
    √ returns a valid RGB with the provided 6-digit HEX color: [color = 'ffffff']
    √ returns a valid RGB with the provided 6-digit HEX color with the hash symbol: [color = '#ffffff']
    √ returns an empty string when the provided value is not a string: [color = 1234]
    √ returns an empty string when the provided color is too short: [color = 'FF']
    √ returns an empty string when the provided color is too long: [color = '#fffffff']
    √ returns an empty string when the provided value is looks like HEX color string but has invalid symbols: [color = '#fffffp']
    √ returns an empty string when the provided value is invalid: [color = '*']
    √ returns an empty string when the provided value is undefined: [color = undefined]

和mockConsole:

export const mockConsole = () => {
  const consoleError = jest.spyOn(console, 'error').mockImplementationOnce(() => undefined);
  return { consoleError };
};

我发现了这个… http://jsfiddle.net/Mottie/xcqpF/1/light/

function rgb2hex(rgb){
    rgb = rgb.match(/^rgba?[\s+]?\([\s+]?(\d+)[\s+]?,[\s+]?(\d+)[\s+]?,[\s+]?(\d+)[\s+]?/i);
    return (rgb && rgb.length === 4) ? "#" +
        ("0" + parseInt(rgb[1],10).toString(16)).slice(-2) +
        ("0" + parseInt(rgb[2],10).toString(16)).slice(-2) +
        ("0" + parseInt(rgb[3],10).toString(16)).slice(-2) : '';
}

试(奖金)

let hex2rgb= c=> `rgb(${c.match(/\w\w/g).map(x=>+`0x${x}`)})`
let rgb2hex=c=>'#'+c.match(/\d+/g).map(x=>(+x).toString(16).padStart(2,0)).join``

让hex2rgb = c = > ' rgb ($ {c.match (w / \ \ w / g) . map (x = > + 0 x $ {x})})”; 让rgb2hex = c = > ' # ' + c.match (\ d + / g) . map (x = > (+ x) .toString (16) .padStart (2,0)) . join '; / /测试 console.log('#0080C0—>'，hex2rgb('#0080C0')); console.log(“rgb(0, 128, 192)——>”,rgb2hex(的rgb (0, 128, 192)));