How can i convert rgb to hex in p5?

rgb2hex.js

// 15538: Uncaught TypeError: Cannot read property 'toString' of undefined

function setup() {
  createCanvas(400,400);
  background(100);
}

function draw() {
    // var s = second();
    // var shex= color(map(s,0,59,0,100));
    // var shex2= hex(s,6);
    // var test_color = color(255, 204, 0);
    // var hexi = String(s);
    
    var c = color('rgb(255, 204, 0)');
    
    
    fill(c);
    rect(10,10,380,300);
    textSize(20);
    fill(255);
    // text(s,width/2-40,height/2);
    // text(shex,width/2-40,height/2 + 30);
    // text("#"+ shex2,width/2-40,height/2 + 60);
    // text(hexi,width/2-40,70);
    // text(typeof hexi,width/2-40,90);
    
    text(c,width/2-40,height/2);
    text(hex(c,6),width/2-40,height/2+30);
}

Or, if you just want to be silly:
var hx='#'+('000000'+(r<<16|g<<8|b).toString(16)).slice(-6); // r, g, and b are ints 0..255

The p5 code above doesn't work... or rather, it did... then it didn't on some colours.

Use thise.

myColor.toString('#rrggbb')

you can rewrite:

  var hx = "#" + hex(r2,2) + hex(g2,2) + hex(b2,2);

as:

  const hx = `#${hex([r2, g2, b2], 2).join('')}`;