A simple random hex color generator.

colorGenerator.ts

interface IColorGradient {
  min: number;
  max: number;
};

interface IDefaultGradients {
  red?: IColorGradient;
  green?: IColorGradient;
  blue?: IColorGradient;
}

let defaultGradientsValues: IDefaultGradients = {
  red: {
    min: 25,
    max: 225,
  },
  green: {
    min: 25,
    max: 225,
  },
  blue: {
    min: 25,
    max: 225,
  },
};

function getRandomColorsArray(amount = 100, colorGradient?: IDefaultGradients) {
  colorGradient = Object.assign(defaultGradientsValues, colorGradient);
  let colorAmount = Math.ceil(Math.cbrt(amount));
  let colors = [];
  let red = getGradienArray(colorGradient.red, colorAmount);
  let green = getGradienArray(colorGradient.green, colorAmount);
  let blue = getGradienArray(colorGradient.blue, colorAmount);
  while (colors.length < amount) {
    let color = '#' +
      red[Math.floor(Math.random() * colorAmount)] +
      green[Math.floor(Math.random() * colorAmount)] +
      blue[Math.floor(Math.random() * colorAmount)];
    if (colors.indexOf(color) === -1) {
      colors.push(color);
    }
  }
  return colors;
}

function getGradienArray(gradient: IColorGradient, colorAmount: number): number[] {
  let color = [];
  let step = gradient.max - gradient.min / colorAmount;
  for (let i = gradient.min; i < gradient.max; i += step) {
    color.push(i.toString(16));
  }
  return color;
}

let colors = getRandomColorsArray();
console.log(colors);