Javascript 处理异步代码以组合多个返回的响应
我正在编写一些查询GithubAPI的异步代码。我正在进行的每个API调用都会通过这段代码运行,我会点击“weeksOfYear”控制台日志。我试图做的是将所有这些api调用捆绑到一个大数组中,这样我就可以一起处理所有数据。我相信这会涉及回调,但我不确定该放在哪里。我在下面包含了我的代码 我相信它正以这种方式回归,因为这一切都在一个承诺之内。当我尝试向代码中添加另一个承诺时,我会得到一个错误,该错误表示“then is undefined”。这是因为我需要返回一个承诺对象。因此,我认为解决办法是使用回调 谢谢Javascript 处理异步代码以组合多个返回的响应,javascript,jquery,callback,promise,Javascript,Jquery,Callback,Promise,我正在编写一些查询GithubAPI的异步代码。我正在进行的每个API调用都会通过这段代码运行,我会点击“weeksOfYear”控制台日志。我试图做的是将所有这些api调用捆绑到一个大数组中,这样我就可以一起处理所有数据。我相信这会涉及回调,但我不确定该放在哪里。我在下面包含了我的代码 我相信它正以这种方式回归,因为这一切都在一个承诺之内。当我尝试向代码中添加另一个承诺时,我会得到一个错误,该错误表示“then is undefined”。这是因为我需要返回一个承诺对象。因此,我认为解决办法是
$.ajax({
method: 'GET',
url: 'https://api.github.com/orgs/lodash/repos' ,
contentType: 'application/json',
beforeSend: function(xhr){
return xhr.setRequestHeader("Authorization", "token adbfde986475bbee66b2e22b4375be4d34adc098")
}
})
.then(function (data){
// console.log('GOT THIS DATA', data);
return data.map(function(val){
return val.name;
});
})
.then(function (newData){
newData.forEach(function(repoName){
pagination(repoName, function(storage) {
storage = storage.filter(function(PR){
if(PR.merged_at !== null){
return true;
}
})
var weeksOfYear = {};
console.log('STORAGE HERE IS', storage);
storage.filter(function(mergedPR){
if (moment(mergedPR.merged_at).year() === 2016){
return true;
}
}).forEach(function(mergedPR){
var weekMerged = moment(mergedPR.merged_at).week();
if(!weeksOfYear[weekMerged]){
weeksOfYear[weekMerged] = 1;
// weeksOfYear[yearMerged] = yearMerged
}else{
weeksOfYear[weekMerged] += 1;
// weeksOfYear[moment(mergedPR.merged_at).year()] = moment(mergedPR.merged_at).year()
}
})
console.log('weeks of Year are', weeksOfYear)
})
})
})
分页看起来是这样的:
var pagination = function (repoName, callback) {
var num = 1;
var storage = [];
function recursiveHelper(repoName, num){
$.ajax({
method: 'GET',
url: 'https://api.github.com/repos/lodash/' + repoName + '/pulls?state=closed&page=' + num,
contentType: 'application/json',
beforeSend: function(xhr){
return xhr.setRequestHeader("Authorization", "token adbfde986475bbee66b2e22b4375be4d34adc098")
}
})
.then(function(numPullRequests){
// console.log('numPullRequests', numPullRequests);
storage = storage.concat(numPullRequests);
if(numPullRequests.length !== 30){
return callback(storage);
}
recursiveHelper(repoName, num + 1);
})
// console.log('this value is', numPullRequests);
}
recursiveHelper(repoName, num)
}
好的,由于分页是异步的,并且不会返回承诺(即使它使用承诺!但它的递归特性使它成为现实),所以对现有代码的最小更改会产生这样的结果
...
.then(function(newData) {
// use Array#map and Promise.all ...
return Promise.all(newData.map(function(repoName) {
// create a Promise
return new Promise(function(resolve, reject) {
pagination(repoName, function(storage) {
storage = storage.filter(function(PR) {
if (PR.merged_at !== null) {
return true;
}
})
var weeksOfYear = {};
console.log('STORAGE HERE IS', storage);
storage.filter(function(mergedPR) {
if (moment(mergedPR.merged_at).year() === 2016) {
return true;
}
}).forEach(function(mergedPR) {
var weekMerged = moment(mergedPR.merged_at).week();
if (!weeksOfYear[weekMerged]) {
weeksOfYear[weekMerged] = 1;
// weeksOfYear[yearMerged] = yearMerged
} else {
weeksOfYear[weekMerged] += 1;
// weeksOfYear[moment(mergedPR.merged_at).year()] = moment(mergedPR.merged_at).year()
}
});
console.log('weeks of Year are', weeksOfYear);
// resolve the promise in the callback
resolve(weeksOfYear);
});
});
}));
}).then(function(result) {
// results is an array of weeksOfYear
});
但是,如果您更改分页
以返回承诺,如下所示
您的代码可以更改为
...
.then(function(newData) {
// again, use Array#map and Promise.all
return Promise.all(newData.map(function(repoName) {
// no need for new Promise as pagination returns a promise
return pagination(repoName)
.then(function(storage) {
storage = storage.filter(function(PR) {
if (PR.merged_at !== null) {
return true;
}
})
var weeksOfYear = {};
console.log('STORAGE HERE IS', storage);
storage.filter(function(mergedPR) {
if (moment(mergedPR.merged_at).year() === 2016) {
return true;
}
}).forEach(function(mergedPR) {
var weekMerged = moment(mergedPR.merged_at).week();
if (!weeksOfYear[weekMerged]) {
weeksOfYear[weekMerged] = 1;
// weeksOfYear[yearMerged] = yearMerged
} else {
weeksOfYear[weekMerged] += 1;
// weeksOfYear[moment(mergedPR.merged_at).year()] = moment(mergedPR.merged_at).year()
}
});
console.log('weeks of Year are', weeksOfYear);
// just return weeksOfYear
return weeksOfYear;
});
}));
}).then(function(result) {
// results is an array of weeksOfYear
});
注意:如果您没有可用的承诺
替换
return Promise.all(newData.map(function(repoName) {
与
及
与
对于第一个答案,您还需要更改
return new Promise(function(resolve, reject) {
pagination(repoName, function(storage) {
//... snip
console.log('weeks of Year are', weeksOfYear);
// resolve the promise in the callback
resolve(weeksOfYear);
});
});
到
pagination(repoName,function(storage){
是一个异步函数吗?当你说bundle所有这些api调用时,哪个“api调用”你是说,因为唯一看起来像api调用的函数是pagination
是的,它太大了,无法粘贴到注释中,很遗憾,它不断地调用github api来收集不同的拉取请求(一次最多可以检索30个,然后将它们合并到一个数组中。我已经添加了我的其余代码,我希望这能澄清问题。这听起来像是Promise.all
的工作。你可以建立一个承诺数组,并将它们传递给Promise.all
。函数传递给then
Promise.al的块l
将收到一系列关于单个承诺的结果。很抱歉,如果您测试了第二个代码,但它坏了,我在错误的位置返回了承诺。如果可用,all()
肯定会工作,但没有证据表明它是。我们所知道的只是jQuery
…因此jQuery.when()
。注意:添加了使用$的更改。
非常感谢!这是一个很好的答案:)
return $.when.apply($, newData.map(function(repoName) {
}).then(function(result) {
// results is an array of weeksOfYear
});
}).then(function() {
// arguments will be weeksOfYear
});
return new Promise(function(resolve, reject) {
pagination(repoName, function(storage) {
//... snip
console.log('weeks of Year are', weeksOfYear);
// resolve the promise in the callback
resolve(weeksOfYear);
});
});
var d = $.Deffered();
pagination(repoName, function(storage) {
//... snip
console.log('weeks of Year are', weeksOfYear);
// resolve the promise in the callback
d.resolve(weeksOfYear);
});
return d.promise();