hex to rgba javascript code example

Example 1: javascript rgb to hex

function rgbToHex(r, g, b) {
  return "#" + ((1 << 24) + (r << 16) + (g << 8) + b).toString(16).slice(1);
}

function hexToRgb(hex) {
  var result = /^#?([a-fd]{2})([a-fd]{2})([a-fd]{2})$/i.exec(hex);
  if(result){
      var r= parseInt(result[1], 16);
      var g= parseInt(result[2], 16);
      var b= parseInt(result[3], 16);
      return r+","+g+","+b;//return 23,14,45 -> reformat if needed 
  } 
  return null;
}
console.log(rgbToHex(10, 54, 120)); //#0a3678
console.log(hexToRgb("#0a3678"));//"10,54,120"

Example 2: convert hex code to rgb javascript

function hexToRgb(hex){
	var result = /^#?([a-f\d]{2}])([a-f\d]{2})([a-f\d]{2})$/i.exec(hex);
  	
 	return result ? {
    	r: parseInt(result[1],  16);
      	g: parseInt(result[2],  16);
  		b: parseInt(result[3],  16);
    } : null;
}
var hex = "#0a3678";
console.log(hexToRgb(hex).r+","+hexToRgb(hex).g+","+hexToRgb(hex).b);//10,54,120

Example 3: javascript add alpha to hex

function addAlpha(color: string, opacity: number): string {
    // coerce values so ti is between 0 and 1.
    const _opacity = Math.round(Math.min(Math.max(opacity || 1, 0), 1) * 255);
    return color + _opacity.toString(16).toUpperCase();
}
addAlpha('FF0000', 1); // returns 'FF0000FF'
addAlpha('FF0000', 0.5); // returns 'FF000080'