Very basic Typescript Color class, allows init with HexString, HexNumber, RGB and RGBA numbers array

Color.ts

class Color implements Iterable<any>{
  private _hex: string;
  private _rgba: RGBA;


  get hex(): string {
    return this._hex;
  }
  get rgba(): RGBA {
    return this._rgba
  }

  constructor(input: ColorInput) {
      if (input === undefined) throw new Error('ColorInput must be a supported type: (HexString/HexNumber/RGB/RGBA/)');
      if (typeof input === 'string') {
        this._hex = Color.normalizeHexString(input);
        this._rgba = Color.hexStringToComponents(this._hex)
      } else if (typeof input === 'number') {
        this._rgba = Color.hexNumberToComponents(input);
        this._hex = Color.componentsToHexString(this._rgba);
      } else if (Array.isArray(input)) {
        if (!(input.length === 4 || input.length === 3)) throw new Error('must use RGB | RGBA as array input');
        this._hex = Color.componentsToHexString(input);
        this._rgba = Color.hexStringToComponents(this._hex);
      } else if (typeof input === 'object') {
        // defaults in invalid pink color
        const { r = 1, g = 0, b = 0.7647058823529411, a = 1 } = input;
        this._hex = Color.componentsToHexString([r,g,b,a]);
        this._rgba = Color.hexStringToComponents(this._hex)
      } else {
        this._hex = Color.normalizeHexString('#ff00c3a');
        this._rgba = Color.hexStringToComponents(this._hex);
      }
  }

  static normalizeHexString(hex: string): HexString {
    const hexNoPound = hex.replace('#', '');
    if (hexNoPound.length < 2 || hexNoPound.length > 8) throw new Error('Invalid hex value: ' + hex);
    let fixHex = '';
    switch (hexNoPound.length) {
      case 2:
        fixHex = `${hexNoPound}${hexNoPound}${hexNoPound}`;
        break;
      case 3: // 0xffff => 0xff_ff_ff
      case 4: // 0xffff => 0xff_ff_ff_ff
        fixHex = `${hexNoPound.split('').map(f => `${f}${f}`).join('')}`;
        break;
      case 5: {// 0xf_f_f_f_f
        const [r1, r2, g1, g2, b] = hexNoPound as any;
        fixHex = `${r1}${r2}${g1}${g2}${b}${b}`;
        break;
      }
      case 6:
      case 8:
        fixHex = hexNoPound // string is correct;
        /* no op*/
        break;
      case 7: {// 0xf_f_f_f_f_f_f
        const [r1, r2, g1, g2, b1, b2, a] = hexNoPound as any;
        fixHex = `${r1}${r2}${g1}${g2}${b1}${b2}${a}${a}`;
        break;
      }
    }
    if (isNaN(parseInt(fixHex, 16))) throw new Error(fixHex + ' is not a hex number.');
    return `#${fixHex}` as HexString;
  }
  static hexStringToComponents(hexStr: string) : RGBA {
      const normalizedHex = Color.normalizeHexString(hexStr).replace('#', '');
      const hex = parseInt(normalizedHex, 16);
    if (isNaN(hex)) throw new Error(hex + ' is not a hex number.');

      let rgba = [1, 1, 1, 1]; // r, g, b, a
      const size = (normalizedHex.length / 2);

      for (let i = size - 1; i >= 0; i--)
        rgba[(size - 1 - i)] = ((hex >> (i * 8)) & 0xff) / 255.0; // 24 / 16 / 8 / 0;
      const [r, g, b, a] = rgba;

      return [r, g, b, a];
  }
  static hexNumberToComponents(hex: number): RGBA {
      return Color.hexStringToComponents(hex.toString(16));
  }
  static componentsToHexString(components: RGB | RGBA): HexString {
    let str = '';
    for (let i = 0; i < components.length; i++) {
      let component = components[i];
      // normalize component value
      if (component <= 0) component = 0;
      else if (component <= 1) component = component * 255.0
      else if (component > 1) component = Math.min(component, 255);
      component = Math.round(component);
      // add it to string as hex
      str += component.toString(16).padStart(2, '0');
    }
    return Color.normalizeHexString(str);
  }

  valueOf() {
    return this._hex;
  }

  toString() {
    return this._hex;
  }

  [Symbol.iterator](): Iterator<number> {
    let currentIndex = 0;
    const rgba = this.rgba;
    const size = rgba.length;
    return {
      next(): IteratorResult<number> {
        if (currentIndex < size) {
          const nextData = currentIndex++
          return {
            value: rgba[nextData],
            done: false,
          }
        } else {
          return { done: true, value: undefined };
        }
      }

    }
  }
}

examples.ts

try {
  console.log(new Color('#f'));
} catch (error) {
  console.log(error.message);
}

try {
  console.log(new Color('#rr'));
} catch (error) {
  console.log(error.message);
}
console.log(new Color('#ff'));
console.log(new Color('#ffa'));
console.log(new Color('#f01a'));
console.log(new Color('#fd01b'));
console.log(new Color('#68ff46'));
console.log(new Color('#405c91a'));
console.log(new Color('#405c91aa'));
try {
  console.log(new Color('#405c91aae'));
} catch (error) {
  console.log(error.message);
}

console.log(new Color('#ff00c3'));
console.log(new Color('#ff00c3a'));
console.log(new Color('#ff00c3a'));
console.log(new Color('#ff00c3a'));
console.log(new Color([1, 0, 0.7647058823529411, 0.6666666666666666]));
console.log(new Color([1, 0, 0.7647058823529411]));
console.log(new Color([255, 0, 255 * 0.7647058823529411, 255 * 0.6666666666666666]));
console.log(new Color(0xff00c3a));
console.log(new Color(0xffaacca));