util.js

// import afterFrame from "../node_modules/afterframe/dist/afterframe.module.js";
import afterFrame from 'afterframe';

export { afterFrame };

export const measureName = 'duration';

let promise = null;
export function afterFrameAsync() {
	if (promise === null) {
		promise = new Promise(resolve =>
			afterFrame(time => {
				promise = null;
				resolve(time);
			})
		);
	}

	return promise;
}

export function measureMemory() {
	if ('gc' in window && 'memory' in performance) {
		// Report results in MBs
		window.gc();
		window.usedJSHeapSize = performance.memory.usedJSHeapSize / 1e6;
	} else {
		window.usedJSHeapSize = 0;
	}
}

export function markRunStart(runId) {
	performance.mark(`run-${runId}-start`);
}

let staticPromise = Promise.resolve();
export function markRunEnd(runId) {
	return staticPromise.then(() => {
		performance.mark(`run-${runId}-end`);
		performance.measure(
			`run-${runId}`,
			`run-${runId}-start`,
			`run-${runId}-end`
		);
	});
}

export function getRowIdSel(index) {
	return `tbody > tr:nth-child(${index}) > td:first-child`;
}

export function getRowLinkSel(index) {
	return `tbody > tr:nth-child(${index}) > td:nth-child(2) > a`;
}

/**
 * @param {string} selector
 * @returns {Element}
 */
export function getBySelector(selector) {
	const element = document.querySelector(selector);
	if (element == null) {
		throw new Error(`Could not find element matching selector: ${selector}`);
	}

	return element;
}

export function testElement(selector) {
	const testElement = document.querySelector(selector);
	if (testElement == null) {
		throw new Error(
			'Test failed. Rendering after one paint was not successful'
		);
	}
}

export function testElementText(selector, expectedText) {
	const elm = document.querySelector(selector);
	if (elm == null) {
		throw new Error('Could not find element matching selector: ' + selector);
	}

	if (elm.textContent != expectedText) {
		throw new Error(
			`Element did not have expected text. Expected: '${expectedText}' Actual: '${elm.textContent}'`
		);
	}
}

export function testElementTextContains(selector, expectedText) {
	const elm = getBySelector(selector);
	if (!elm.textContent.includes(expectedText)) {
		throw new Error(
			`Element did not include expected text. Expected to include: '${expectedText}' Actual: '${elm.textContent}'`
		);
	}
}

let count = 0;
const channel = new MessageChannel();
const callbacks = new Map();
channel.port1.onmessage = e => {
	let id = e.data;
	let fn = callbacks.get(id);
	callbacks.delete(id);
	fn();
};
let pm = function(callback) {
	let id = ++count;
	callbacks.set(id, callback);
	this.postMessage(id);
}.bind(channel.port2);

export function nextTick() {
	return new Promise(r => pm(r));
}

export function mutateAndLayoutAsync(mutation, times = 1) {
	return new Promise(resolve => {
		requestAnimationFrame(() => {
			for (let i = 0; i < times; i++) {
				mutation(i);
			}
			pm(resolve);
		});
	});
}

export const sleep = ms => new Promise(r => setTimeout(r, ms));