我将捕获放在最后，但它们至少在一个特定实例中返回空对象。对于任何不为人知的事情是否需要捕获，或者只是把我搞砸了？
$( document).ready(function(){
app.callAPI()//a chainable a RSVP wrapper around a jquery call, with its own success() fail() passing forward to the wrapper, so it will either be a resolved or rejected thenable to which is now going to be chained
.then(
function(env) {
//set the property you needed now
app.someSpecialEnvObj = env;
},
function(rejectMessage){
console.log('call.API() cant set some special env object..');
console.log(rejectMessage);
}
)
.catch(
function(rejectMessage){
if(rejectMessage){
//a just incase, DOES IT HAVE VALUE, for somebody that may have not done their homework in the parent calls?
console.log('you have some kind of legitimate error, maybe even in callAPI() that is not part of any problems inside them. you may have forgotton handle something at an early state, your so lucky this is here!)
} else {
console.log('can this, and or will this ever run. i.e., is there any value to it, when the necessity to already be logging is being handled in each and every then already, guaranteeing that we WONT be missing ANYTHING')
}
}
);
});
这是错的吗？或者它是否有某种用途，即使我仍然对.then(resolve, reject)所有父链 then-ables 中的所有方法使用使用错误/拒绝处理程序？
编辑：更好的代码示例，我希望。我想我可能仍然在命名中使用某种反模式，我rejectMessage在我的例子中，它是 jqXhr 对象，对吧？
所以也许我应该准确地命名它们或什么？即jqXhr？顺便说一句，我喜欢在每个内部当场拒绝它的原因then()，如果有错误，是因为这样我可以大量记录每个单独的呼叫，如果那里特别有问题，那我就没有追踪任何东西。微博，因为我可以。
Promise 正在帮助以这种方式打开调试的世界。
这是我尝试过的三个示例。我更喜欢方法 1 和方法 2，我绝不会回到方法 3，这是我在应许之地开始的地方。
//method 1
app.rsvpAjax = function (){
var async,
promise = new window.RSVP.Promise(function(resolve, reject){
async = $.extend( true, {},app.ajax, {
success: function(returnData) {
resolve(returnData);
},
error: function(jqXhr, textStatus, errorThrown){
console.log('async error');
console.log({jqXhr: jqXhr, textStatus: textStatus, errorThrown: errorThrown});
reject({ jqXhr: jqXhr, textStatus: textStatus, errorThrown: errorThrown}); //source of promise catch data believe
}
});
$.ajax(async); //make the call using jquery's ajax, passing it our reconstructed object, each and every time
});
return promise;
};
app.callAPI = function () {
var promise =app.rsvpAjax();
if ( !app.ajax.url ) {
console.log("need ajax url");
promise.reject(); //throw (reject now)
}
return promise;
};
//method 2
app.ajaxPromise = function(){
var promise, url = app.ajax.url;
var coreObj = { //our XMLHttpRequestwrapper object
ajax : function (method, url, args) { // Method that performs the ajax request
promise = window.RSVP.Promise( function (resolve, reject) { // Creating a promise
var client = new XMLHttpRequest(), // Instantiates the XMLHttpRequest
uri = url;
uri = url;
if (args && (method === 'POST' || method === 'PUT')) {
uri += '?';
var argcount = 0;
for (var key in args) {
if (args.hasOwnProperty(key)) {
if (argcount++) {
uri += '&';
}
uri += encodeURIComponent(key) + '=' + encodeURIComponent(args[key]);
}
}
}
client.open(method, uri);
client.send();
client.onload = function () {
if (this.status == 200) {
resolve(this.response); // Performs the function "resolve" when this.status is equal to 200
}
else {
reject(this.statusText); // Performs the function "reject" when this.status is different than 200
}
};
client.onerror = function () {
reject(this.statusText);
};
});
return promise; // Return the promise
}
};
// Adapter pattern
return {
'get' : function(args) {
return coreObj.ajax('GET', url, args);
},
'post' : function(args) {
return coreObj.ajax('POST', url, args);
},
'put' : function(args) {
return coreObj.ajax('PUT', url, args);
},
'delete' : function(args) {
return coreObj.ajax('DELETE', url, args);
}
};
};
app.callAPI = function () {
var async, callback;
async =app.ajaxPromise() ; //app.ajaxPromise() is what creates the RSVP PROMISE HERE<
if(app.ajax.type === 'GET'){async = async.get();}
else if(app.ajax.type === 'POST') {async = async.post();}
else if(app.ajax.type === 'PUT'){async = async.put();}
else if(app.ajax.type === 'DELETE'){ async = async.delete();}
callback = {
success: function (data) {
return JSON.parse(data);
},
error: function (reason) {
console.log('something went wrong here');
console.log(reason);
}
};
async = async.then(callback.success)
.catch(callback.error);
return async;
};
//method 3 using old school jquery deferreds
app.callAPI = function () {
//use $.Deferred instead of RSVP
async = $.ajax( app.ajax) //run the ajax call now
.then(
function (asyncData) { //call has been completed, do something now
return asyncData; //modify data if needed, then return, sweet success
},
function(rejectMessage) { //call failed miserably, log this thing
console.log('Unexpected error inside the callApi. There was a fail in the $.Deferred ajax call');
return rejectMessage;
}
);
return async;
};
我也在某个地方运行它onready作为另一个备份。
window.RSVP.on('error', function(error) {
window.console.assert(false, error);
var response;
if(error.jqXhr){
response = error.jqXhr;
} else {
//response = error;
response = 'is this working yet?';
}
console.log('rsvp_on_error_report')
console.log(response);
});
编辑错误示例
//one weird error I can't understand, an empty string("")?
{
"jqXhr": {
"responseText": {
"readyState": 0,
"responseText": "",
"status": 0,
"statusText": "error"
},
"statusText": "error",
"status": 0
},
"textStatus": "error",
"errorThrown": "\"\""
}
//another wierd one, but this one comes from a different stream, the RSVP.on('error') function
{
"readyState": 0,
"responseText": "",
"status": 0,
"statusText": "error"
}