Snippet Zone

Simple Way to Validate CSS Colors

```
function isColor(col) {
```
```
  const cache = isColor[col]
```
```
  if (cache != null) {
```
```
    console.log('- reading cache')
```
```
    return cache
```
```
  }
```
```
  isColor.el.style = ''
```
```
  isColor.el.style.color = col
```

  return isColor[col] = !!isColor.el.style.color

```
}
```

isColor.el = document.createElement('div')

```
 
```
```
 
```

console.log('is "red" a color?', isColor('red'))

console.log('from the cache: ', isColor('red'))

```
 
```

console.log('is "rgbx(1, 2, 3)" a color?', isColor('rgbx(1, 2, 3)'))

```
 
```

console.log('is "#0f0" a color?', isColor('#0f0'))

```
 
```

console.log('is "hsl(192, 50%, 50%)" a color?', isColor('hsl(192, 50%, 50%)'))

console.log('from the cache: ', isColor('hsl(192, 50%, 50%)'))

```
 
```

console.log('is "lab(2000.1337% -8.6911 -159.131231 / .987189732)" ?',

  isColor('lab(2000.1337% -8.6911 -159.131231 / .987189732)'))

```
 
```

console.log('is "snippetZone" ?', isColor('snippetZone'))

I find this technique is usually good enough to validate colors…

July 17, 2023

// color // css // dom // graphics // hacks // hex // html // javascript // tricks

Other Gates from NAND

```
const nand = ([a, b]) => +!(a & b)
```
```
 
```
```
const not = ([a]) => nand([a, a])
```
```
 
```

const and = ([a, b]) => nand([nand([a, b]), nand([a, b])])

```
 
```

const or = ([a, b]) => nand([nand([a, a]), nand([b, b])])

```
 
```
```
const nor = ([a, b]) => 
```
```
  nand([ 
```

    nand([nand([a, a]), nand([b, b])]),

```
    nand([nand([a, a]), nand([b, b])])
```
```
  ])
```
```
 
```
```
const xor = ([a, b]) =>
```
```
  nand([
```
```
    nand([a, nand([a, b])]),
```
```
    nand([b, nand([a, b])])
```
```
  ])
```
```
 
```
```
const xnor = ([a, b]) => 
```
```
  nand([ 
```
```
    nand([nand([a, a]), nand([b, b])]),
```
```
    nand([a, b])
```
```
  ])
```
```
 
```
```
 
```
```
const inputs = [
```
```
  [0, 0],
```
```
  [0, 1],
```
```
  [1, 0],
```
```
  [1, 1]
```
```
]
```
```
 
```

const testGate = ({ gate, truth, result }) => console.log(

```
  gate + ' matches truth? ', 
```
```
  truth+'' === result+'' ? 
```

    'yes :D' : `nope :( ${truth} ${result}`

```
)
```
```
 
```
```
testGate({
```
```
  gate: 'NAND',
```
```
  truth: [1, 1, 1, 0],
```
```
  result: inputs.map(nand)
```
```
})
```
```
 
```
```
testGate({
```
```
  gate: 'NOT',
```
```
  truth: [0, 1],
```
```
  result: [[1], [0]].map(not)
```
```
})
```
```
 
```
```
testGate({
```
```
  gate: 'AND',
```
```
  truth: [0, 0, 0, 1],
```
```
  result: inputs.map(and)
```
```
})
```
```
 
```
```
testGate({
```
```
  gate: 'OR',
```
```
  truth: [0, 1, 1, 1],
```
```
  result: inputs.map(or)
```
```
})
```
```
 
```
```
testGate({
```
```
  gate: 'NOR',
```
```
  truth: [1, 0, 0, 0],
```
```
  result: inputs.map(nor)
```
```
})
```
```
 
```
```
testGate({
```
```
  gate: 'XOR',
```
```
  truth: [0, 1, 1, 0],
```
```
  result: inputs.map(xor)
```
```
})
```
```
 
```
```
testGate({
```
```
  gate: 'XNOR',
```
```
  truth: [1, 0, 0, 1],
```
```
  result: inputs.map(xnor)
```
```
})
```

Use NAND to create a bunch of other gates 😀 – I used this wikipedia article for reference

July 16, 2023

// arrays // golfed // humor // javascript // math

Multiplicative Persistence

```
const multp = (val, count = 1, res) => 
```
```
  (res = (val + '').split``
```

    .reduce((a, b) => a * b, 1) + '').length > 1 ?

```
      multp(res, count + 1) : count
```
```
 
```
```
 
```
```
console.log('test:', multp(2678789))
```

Started watching this youtube video from numberphile and instantly made this half-golfed thing

Found this:

f=n=>[n,...n>9?f(eval([...n+''].join`*`)):[]]

By Arnauld over at codegolf.stackexchange

will definitely remember: [...n+'']

June 10, 2023

// golfed // hacks // humor // javascript // math

Parametric Equation for Rectangle

// from http://math.stackexchange.com/questions/69099/equation-of-a-rectangle

```
const rect = (px, py, rx, ry, t) => ({
```

  x: px + rx + rx * (Math.abs(Math.cos(t)) * Math.cos(t) + Math.abs(Math.sin(t)) * Math.sin(t)),

  y: py + ry + ry * (Math.abs(Math.cos(t)) * Math.cos(t) - Math.abs(Math.sin(t)) * Math.sin(t))

```
})
```
```
 
```
```
const SIZE = 200
```
```
 
```
```
const c = document.body.appendChild(
```

  Object.assign(document.createElement`canvas`,

```
    { width: SIZE, height: SIZE }
```
```
  )).getContext`2d`
```
```
 
```
```
c.fillStyle = 'black'
```
```
c.fillRect(0, 0, SIZE, SIZE)
```
```
 
```
```
let t = 0
```
```
setInterval(() => {
```

  const { x, y } = rect(20, 20, 60, 70, t)

```
  c.fillStyle = 'rgba(255, 0, 0, .1)'
```
```
  c.fillRect(x, y, 10, 10)
```
```
  t += .05
```
```
}, 16)
```

Wanted to know how to do this for something back in 2015. Great math stackexchange answer here: http://math.stackexchange.com/questions/69099/equation-of-a-rectangle

Could be optimized but leaving as is to match:

x = p(|cos t|cos t + |sin t| sin t)
y = p(|cos t|cos t - |sin t| sin t)

One small change here is to add the width and height to the offset so that it draws from the upper left hand corner instead of the center…

April 14, 2023

// animation // graphics // javascript // math

Divide Rectangle Into Smaller Rectangles

const rand = num => ~~(Math.random() * num)

```
 
```
```
let rectNum = 2 + rand(10)
```
```
let rectCount = 0
```
```
 
```

document.body.appendChild(document.createElement('div')).innerText =

```
  'click anywhere to regenerate'
```
```
 
```
```
function reset() {
```

  ;[...document.querySelectorAll('.rect')].forEach(rect => rect.remove())

```
  rectNum = 2 + rand(10)
```
```
  rectCount = 0
```
```
  newRect(300, 300, 50, 50)
```
```
}
```
```
reset()
```
```
onpointerup = reset
```
```
 
```
```
function newRect(w, h, xp, yp) {
```

  const rect = document.body.appendChild(document.createElement('div'))

```
 
```
```
  rect.classList.add('rect')
```
```
  rectCount++
```
```
 
```
```
  Object.assign(rect.style, {
```
```
    position: 'absolute',
```
```
    left: `${xp}px`,
```
```
    top: `${yp}px`,
```
```
    width: `${w}px`,
```
```
    height: `${h}px`,
```
```
    outline: `1px solid black`,
```
```
  })
```
```
 
```
```
  const props = {
```
```
    x: xp,
```
```
    y: yp,
```
```
    height: h,
```
```
    width: w,
```
```
    seed: rand(3),
```
```
    divide() {
```

      const div = 2 + rand(5 * Math.random() * Math.random())

```
      if (rand(2) == rand(2)) {
```

        const newHeight = this.height / div

```
 
```

        newRect(this.width, this.height - newHeight, this.x, this.y)

        newRect(this.width, newHeight, this.x, this.y + this.height - newHeight)

```
      } else {
```
```
        const newWidth = w / div
```

        newRect(this.width - newWidth, this.height, this.x, this.y)

        newRect(newWidth, this.height, this.x + this.width - newWidth, this.y)

```
      }
```
```
      rect.remove()
```
```
    },
```
```
  }
```
```
  window.requestAnimationFrame(() => {
```
```
    if (rectCount < rectNum) {
```
```
      props.divide()
```
```
    } else {
```
```
      console.log('DONE!')
```
```
    }
```
```
  })
```
```
}
```

This snippet comes to mind from time to time – one easy way to divide a rectangle into smaller rectangles- I actually went back and looked it up as it was an answer to a student question from 2006. The original one was written in ActionScript 2. Have a look:

```
var wormNum:Number = 123;
```
```
var wormCount:Number = 0;
```
```
newWorm(400, 400, 0, 0);
```
```
this.onEnterFrame = function() {
```
```
	if (wormCount < wormNum) {
```
```
		for (var props:String in this) {
```
```
			if (this[props]._x != undefined) {
```
```
				this[props].divide();
```
```
			}
```
```
		}
```
```
	}
```
```
};
```
```
function newWorm(w, h, xp, yp) {
```

	var currWorm:MovieClip = this.createEmptyMovieClip("box"+wormCount, this.getNextHighestDepth());

```
	wormCount++;
```
```
	box(w, h, currWorm, random(0xFFFFFF));
```
```
	currWorm._x = xp;
```
```
	currWorm._y = yp;
```
```
	currWorm.seed = random(3);
```
```
	currWorm.divide = function() {
```

		var div = random(4)+(1+Math.random()*1);

```
		if (random(2) == random(2)) {
```
```
			// divide vertically
```
```
			var nh:Number = this._height/div;
```

			newWorm(this._width, this._height-nh, this._x, this._y);

			newWorm(this._width, nh, this._x, this._y+this._height-nh);

```
		} else {
```
```
			// divide horizonatlly
```
```
			var nw:Number = this._width/div;
```

			newWorm(this._width-nw, this._height, this._x, this._y);

			newWorm(nw, this._height, this._x+this._width-nw, this._y);

```
		}
```
```
		this.removeMovieClip();
```
```
	};
```
```
}
```

function box(w:Number, h:Number, mc:MovieClip, col:Number):Void {

```
	with (mc) {
```
```
		lineStyle(0, 0, 20);
```
```
		beginFill(col, 10);
```
```
		moveTo(0, 0);
```
```
		lineTo(w, 0);
```
```
		lineTo(w, h);
```
```
		lineTo(0, h);
```
```
		endFill();
```
```
	}
```
```
}
```

Don’t remember why I called them worms instead of rectangles, some AS2 types floating around…

December 28, 2022

// graphics // humor // javascript // math // oldschool // random // speedcoding

Older Posts

Newer Posts

Simple Way to Validate CSS Colors

Other Gates from NAND

Multiplicative Persistence

Parametric Equation for Rectangle

Divide Rectangle Into Smaller Rectangles

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