WEB+DB PRESS Vol.71『プログラマのためのjQuery再入門』Deferredオブジェクト周りの写経

list10.js

var cache = {};
function getFromCacheOrAPI(url) {
    if (!cache[url]) {
        cache[url] = $.get(url);
    }

    return cache[url];
}

getFromCacheOrAPI('/api/foo').done(function(data) {
    console.log(data.msg);
});

list5.js

$.get('/api/foo').then(function(data1) {
    return $.get('/api/bar', {id: data1.id});
}).done(function(data2) {
    $('#target').text(data2.msg);
}).fail(function() {
    console.error('Error!');
});

list6.js

var d  =  $.Deferred();
console.log(d.state()); // pending

d.resolve();
console.log(d.state()); // resolved

d.reject();
console.log(d.state()); // resolved

list7.js

function getDeferred() {
    return $.Deferred().done(function(arg) {
        console.log('done1: ' + arg);
    }).fail(function(arg) {
        console.log('fail: ' + arg);
    }).always(function(arg) {
        console.log('always: ' + arg);
    }).done(function(arg) {
        console.log('done2: ' + arg);
    });
}

// done1: Resolve!
// always: Resolve!
// done2: Resolve!
var resolved = getDeferred().resolve('Resolve!');

// fail: Reject!
// always: Reject!
getDeferred().reject('Reject!');

// done3: Resolve!
resolved.done(function(arg) {
    console.log('done3: ' + arg);
});

list8+9.js

function wait(sec, opt_arg) {
    var d = $Deferred();
    setTimeout(function() {
        d.resolve(opt_arg);
    }, sec * 1000);

    return d.promise();
}

var promise = wait(3).done(function() {
    console.log('3秒後に実行される');
});

promise.resolve('Promiseオブジェクトからはresolveメソッドが無いためエラー');

$.Deferred().resolve('Resolve!').then(function(arg) {
    console.log(arg); // Resolve!

    return wait(1, 'Wait!').done(function(arg) {
        console.log('First: ' + arg); // First: Wait!
    });
}).done(function(arg) {
    console.log('Second: ' + arg); // Second: Wait!
});