Asynchronous Javascript Development

async-example-01.js

var getContent = function () {
	return 'Hello World!';
};

console.log(getContent()); // 'Hello World!'

async-example-02.js

var getContent = function (callback) {
	callback('Hello World!');
};

getContent(console.log); // 'Hello World!'

async-example-03.js

var getContent = function (callback) {
	Xhr.ajax({
		url: 'hello.txt',
		success: callback,
		error: function () {
			// Whoa error!
		}
	});
};

getContent(console.log); // 'Hello World!'

async-example-04.js

var getContent = function () {
	return new Promise(function (fulfill, reject) {
		Xhr.ajax({
			url: 'hello.txt',
			success: fulfill,
			error: reject
		});
	});
};

getContent().then(console.log);

async-example-05.js

var getContent = function () {
	return new Promise(function (fulfill, reject) {
		Xhr.ajax({
			url: 'noexist.txt',
			success: fulfill,
			error: function (error, xhr) {
				reject(error + ': ' + xhr.statusText);
			}
		});
	});
};

getContent()
	.then(console.log)
	.catch(console.log)
	.then(function () {
		console.log('Complete!');
	});

async-example-06.js

var files = ['file1.txt', 'file2.txt', 'file3.txt'];

var getContent = function (url) {
	return new Promise(function (fulfill, reject) {
		Xhr.ajax({
			url: url,
			success: fulfill,
			error: reject
		});
	});
};

Promise.all(files.map(getContent))
	.then(function (values) {
		values.forEach(console.log);
	})
	.catch(console.log)
	.then(function () {
		console.log('Complete!');
	});

Asynchronous Javascript

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