# How to know if a variable is a color?

**URL:** <https://discourse.processing.org/t/how-to-know-if-a-variable-is-a-color/47945>\
**Category:** Coding Questions\
**Created:** [February 23, 2026, 9:12am UTC](https://discourse.processing.org/t/how-to-know-if-a-variable-is-a-color/47945 "2026-02-23T09:12:50Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![EricRogerGarcia](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/ericrogergarcia/32/21029_2.png) [@EricRogerGarcia](https://discourse.processing.org/u/EricRogerGarcia)\
**Post date:** [February 23, 2026, 9:12am UTC](https://discourse.processing.org/t/how-to-know-if-a-variable-is-a-color/47945/1 "2026-02-23T09:12:50Z")

</div>

_**(Another funny question)**_ 🙃

if `let c=color(15,20,56)`

`typeof c : object`

and

`c.constructor.name : nothing !!!`

**Help**! How can I check that it is indeed a color ???

* * *

**This code doesn’t work obviously with colors !**

```auto
function className(object) {
  return object.constructor.name;
}

class V {
  static verif=true;

  static get(a, s, n) { // (anyType, type in a string, this) : any
    if (!V.verif) {
      return a;
    } else if ( typeof a === s) {
      return a;
    } else if (typeof a === 'object') {
      if (className(a)===s) return a;
      else {
        let type = typeof a;
        bugMessage("V Error, in : "+n+", asked : "+s+", but it was : "+type, true);
        return 0;
      }
    } else {
      let type = typeof a;
      bugMessage("V Error, in : "+n+", asked : "+s+", but it was : "+type, true);
      return 0;
    }
  }
}

```

**P.S.** In my project, I want to help the (future) user with explicit error messages.

In the many parameters of a theme for the GUI part, an error quickly arrived. As javascript is more lax for types than Java (Processing), which has advantages too, I try to add error messages in my program.

---

<div class="post-metadata">

**Author:** ![josephh](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/josephh/32/210_2.png) [@josephh](https://discourse.processing.org/u/josephh)\
**Post date:** [February 23, 2026, 9:21am UTC](https://discourse.processing.org/t/how-to-know-if-a-variable-is-a-color/47945/2 "2026-02-23T09:21:42Z")

</div>

Hi @EricRogerGarcia,

Since `p5.Color` is a class/constructor, you can use [`instanceof`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/instanceof) to check if an object has that constructor in its prototype chain (meaning it’s an instance of `p5.Color`):

```javascript
const c = color(255);
console.log(typeof c); // object
console.log(c.constructor.name); // Color
console.log(c instanceof p5.Color); // true

```

---

<div class="post-metadata">

**Author:** ![EricRogerGarcia](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/ericrogergarcia/32/21029_2.png) [@EricRogerGarcia](https://discourse.processing.org/u/EricRogerGarcia)\
**Post date:** [February 23, 2026, 12:20pm UTC](https://discourse.processing.org/t/how-to-know-if-a-variable-is-a-color/47945/3 "2026-02-23T12:20:33Z")

</div>

thanks : it works !! ! yesss !

```auto
"use strict";

// Workaround a P5 current problem with static field
p5.disableFriendlyErrors = true;

function className(object) {
  return object.constructor.name;
}

class V {
  static verif=true;

  static get(a, s, n) { // (anyType, type in a string, this) : any
    if (!V.verif) return a; // when debugging is finished : V.verif=false;
    else if (typeof a === s) return a; // for primitive types
    else if (typeof a === 'object') {
      if (className(a)===s) return a; // for classes (declared with "class" word)
      else if (s=="color") {
        if (a instanceof p5.Color) return a;
        else return V.error(a, s, n);
      } else if (s=="font") {
        if (a instanceof p5.Font) return a;
        else return V.error(a, s, n);
      } else return V.error(a, s, n);
    } //not an object !?
    return V.error(a, s, n);
  } // end get()

  static error(a, s, n) { //+ (anyType,String,object) : int
    let type = typeof a;
    bugMessage("V Error, in : "+n+", asked : "+s+", but it was : "+type, true);
    return 0;
  }
}

```

**P.S.** I don’t know why I forgot “instanceof” !!!