$q两种常见使用方式

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$q(function resolver (resolve, reject) {})

var iWantResolve = true;

function es6promise() {
    return $q(function (resolve, reject) {
        $timeout(function () {
            if (iWantResolve) {
                resolve("es6promise resolved");
            } else {
                reject("es6promise reject");
            }
        }, 1000)
    })
}

• promise.then(successCb, errCb, notifyCb)
  • 其中successCb 将在 promise resolve 后被调用, errCb 将在 promise reject 后被调
  • notifyCb 将在 deferred.notify 后被调用, 可以多次调用
  • promise.catch == promise.then(null, errCb), 用于处理之前没有被处理的 rejected promise
  • promise.finally 将最后被调用, 一般用于资源释放的清理操作

es6promise()
    .then(function (data) {
        console.log(data);
    })
    .catch(function (err) {
        console.log(err);
    });

// if(iWantResolve == true) output: es6promise resolved
// if(iWantResolve = false) output: es6promise reject

$q.defer()

function commonJsPromise() {
    var deferred = $q.defer();
    $timeout(function () {
        deferred.notify("commonJS notify");
        if (iWantResolve) {
            deferred.resolve("commonJS resolved");
        } else {
            deferred.reject("commonJS reject");
        }
    }, 500);
    return deferred.promise;
}

commonJsPromise()
    .then(function /** success callback**/(data) {
        console.log(data);
    }, function /** error callback **/ (err) {
        console.log(err);
    }, function /** progress callback **/ (update) {
        console.log(update);
    });