A very minimal p5.js polyfill for when you want to write basic p5.js code but not import the whole kitchen sink.

	// Add this object somewhere before your p5.js code.
	let context;
	window.p = {
	PI: Math.PI,
	HALF_PI: Math.PI / 2,
	random: (a, b) => {
	if (a !== undefined && b !== undefined) {
	return Math.floor(Math.random() * b) + a;
	} else {
	// Assume a is an array.
	const i = Math.floor(Math.random() * a.length);
	return a[i];
	}
	},
	fill: (c) => context.fillStyle = c,
	stroke: (c) => context.strokeStyle = c,
	noFill: () => context.fillStyle = 'transparent',
	noStroke: () => context.strokeStyle = 'transparent',
	push: () => context.save(),
	pop: () => context.restore(),
	translate: (x,y) => context.translate(x,y),
	scale: (x,y) => context.scale(x,y),
	rect: (x,y,w,h) => {
	context.fillRect(x, y, w, h);
	context.strokeRect(x, y, w, h);
	},
	circle: (x,y,d) => {
	context.beginPath();
	context.arc(x, y, d/2, 0, Math.PI * 2, false);
	context.fill();
	context.stroke();
	},
	arc: (x, y, w, h, start, stop, slice=false) => {
	context.beginPath();
	if (!slice) {
	context.moveTo(x, y);
	}
	context.arc(x, y, w/2, start, stop);
	context.closePath();
	context.fill();
	context.stroke();
	}
	}




	// Write your p5.js code in slightly bastardized "instance" mode:
	function sketch(p) {
	setup();

	function setup() {
	// ...
	// If you need a drawing loop you could add this in a requestAnimationFrame.
	draw();
	}

	function draw() {
	p.fill('red');
	p.rect(0, 0, p.width, p.height);

	p.push();
	// Center.
	p.translate(p.width/2, p.height);
	// This is an obviously contrived example.
	p.arc(0, 0, 40, 40, 0, p.HALF_PI);
	p.pop();

	// etc.
	}
	}

	// And then instantiate the instance mode. This looks way simpler than the p5.js instance mode
	// because I'm assuming you know where your canvas lives already. I sure do.
	sketch(p);