iterator_result_reuse.mts

import { bench, do_not_optimize, run } from './node_modules/mitata/src/main.mjs';

const ub = 100_000;

const adHoc = {
	[Symbol.iterator]() {
		return {
			i: 0,
			next() {
				return this.i < ub ? { value: this.i++ } : { done: true }
			}
		}
	}
}

const adHocReuse = {
	[Symbol.iterator]() {
		const result = { value: 0, done: false }
		return {
			i: 0,
			next() {
				if(this.i < ub) {
					result.value = this.i++;
					return result;
				}
				result.done = true;
				return result;
			}
		}
	}
}

const native = {
	data: Array.from({ length: ub }, (_, i) => i),
	[Symbol.iterator]() {
		return this.data.values();
	}
}

const generator = {
	*[Symbol.iterator]() {
		for(let i = 0; i < ub; i++) yield i;
	}
}

const generatorDelegation = {
	data: Array.from({ length: ub }, (_, i) => i),
	*[Symbol.iterator]() {
		yield* this.data;
	}
}


bench(`0 .. ${ub} native`, () => {
	let i = 0;
	for(let j of native) {
		i += j;
	}
	return do_not_optimize(i)
});

bench(`0 .. ${ub} ad-hoc`, () => {
	let i = 0;
	for(let j of adHoc) {
		i += j!;
	}
  	return do_not_optimize(i)
});

bench(`0 .. ${ub} ad-hocreusing IteratorResult`, () => {
	let i = 0;
	for(let j of adHocReuse) {
		i += j!;
	}
  	return do_not_optimize(i)
});

bench(`0 .. ${ub} generator`, () => {
	let i = 0;
	for(let j of generator) {
		i += j!;
	}
  	return do_not_optimize(i)
});

bench(`0 .. ${ub} generator delegation`, () => {
	let i = 0;
	for(let j of generatorDelegation) {
		i += j!;
	}
  	return do_not_optimize(i)
});

await run();