Typescript Library - hexFromArgb - Missing Alpha

[wojtek-viirtue]

The hexFromArgb function is missing the alpha component in its output. This is also related to Issue: Typescript Library - argbFromHex - Incorrect Parsing #33

Input: 2147483648
Expected: #80
Actual: #000000

material-color-utilities/typescript/utils/string_utils.ts

Lines 28 to 42 in 9e67d5e

	export const hexFromArgb = (argb: number) => {
	const r = colorUtils.redFromArgb(argb);
	const g = colorUtils.greenFromArgb(argb);
	const b = colorUtils.blueFromArgb(argb);
	const outParts = [r.toString(16), g.toString(16), b.toString(16)];
	// Pad single-digit output values
	for (const [i, part] of outParts.entries()) {
	if (part.length === 1) {
	outParts[i] = '0' + part;
	}
	}
	return '#' + outParts.join('');
	};

[wojtek-viirtue]

Again...know you guys aren't accepting pull requests but here's a working version with minimal changes:

/**
 * @param argb ARGB representation of a color.
 * @return Hex string representing color, ex. #ff0000 for red.
 */
export const hexFromArgb = (argb: number) => {
  const a = colorUtils.alphaFromArgb(argb);
  const r = colorUtils.redFromArgb(argb);
  const g = colorUtils.greenFromArgb(argb);
  const b = colorUtils.blueFromArgb(argb);
  const outParts = [r.toString(16), g.toString(16), b.toString(16), a.toString(16)];

  // Pad single-digit output values
  for (const [i, part] of outParts.entries()) {
    if (part.length === 1) {
      outParts[i] = '0' + part;
    }
  }

  return '#' + outParts.join('');
};

[WillsterJohnson]

Going to see about implementing this.
My idea is to have no effect on the current operation of any fromArgb functions, but to provide an optional final argument alpha: boolean = false, which when set to true will include the alpha value in the returned data.
I also intend to track the movement of color data through the library's various functions and classes and ensure that alpha data is preserved such that you can abuse and mangle data to your hearts content and expect the alpha value which went in to also come out the other end.
Above all though, existing code will perform exactly as it currently does.