Javascript 在继续循环之前完成回调?
所以我已经在这上面呆了一段时间了。如果有人能帮我解决这个问题,我会非常感激!我想要的是在循环中继续之前完成函数及其回调。在用户在文本区域中输入英文文本并单击翻译按钮后,我称之为“translate_all”。(“Method”、“g_loop”、“g_where”和“go”是全局变量。)最终我想要的是将输入的英语短语翻译成数组中的下一种语言,然后将其翻译回英语,看看是否有差异,然后继续遍历所有语言 我试过许下诺言,但老实说,我无法相信。我尝试了这种“黑客式”的方法,在while循环中捕获循环,直到在回调后更改全局变量“go”。但是,当我运行这个程序时,浏览器会冻结,我认为这是因为尽管这种方法阻止了循环继续,但它被困在循环中,以至于它从未收到来自回调的消息,即“go”已更改。也许我可以像很快推荐给我的那样做一些事件监听器,但我不确定。我觉得我离得太近了,想让它发挥作用这么长时间,我都快疯了。感谢您的任何帮助!谢谢 我有这个:Javascript 在继续循环之前完成回调?,javascript,loops,callback,google-api,google-translate,Javascript,Loops,Callback,Google Api,Google Translate,所以我已经在这上面呆了一段时间了。如果有人能帮我解决这个问题,我会非常感激!我想要的是在循环中继续之前完成函数及其回调。在用户在文本区域中输入英文文本并单击翻译按钮后,我称之为“translate_all”。(“Method”、“g_loop”、“g_where”和“go”是全局变量。)最终我想要的是将输入的英语短语翻译成数组中的下一种语言,然后将其翻译回英语,看看是否有差异,然后继续遍历所有语言 我试过许下诺言,但老实说,我无法相信。我尝试了这种“黑客式”的方法,在while循环中捕获循环,直
var translate_all = function translate_all () {
// set global g_where to this div to append an image
g_where = $("#g_div");
g_where.append("<img alt='Google Logo' src='/img/google_g_medium.png'/><br>");
// get the text the user input
var a_text = $("#accuracy_text").val();
// translation codes for api
var language_codes = ["en", "ar", "bg", "ca", "hr", "cs", "da", "nl", "et", "fi", "fr", "de", "el", "ht", "id", "it", "ko", "lv", "lt", "ms", "mt", "no", "fa", "pl", "pt", "ro", "ru", "sl", "sl", "es", "th", "tr", "uk", "ur", "vi"];
// set global g_loop to what text the user input
g_loop = a_text;
// start a loop
for (var i = 1; i < language_codes.length; i++)
{
// error checking and trying to debug and see what is wrong
console.log("working")
// define which callback i want to run
method = 2;
// this callback sets the response from google placed in g_response to g_loop; it translates from one language in loop to the next
GoogleTranslate(g_loop, language_codes[i-1], language_codes[i]);
console.log("continue");
// THIS is where i try to get the loop to stop until the callback has run because this loop is only able to break when the callback has finished
while (go == 0)
{
if (go == 1)
{
break;
}
}
// set go back to zero
go = 0;
// set g_where and append the response to the div
g_where = $("#g_div");
g_where.append(g_response)
method = 1;
// this translates the initial response back to english to see if there is a difference and appends it to the div
GoogleTranslate(g_loop, language_codes[i], "en");
// trying to make sure the callback is executed again before continuing
while (go == 0)
{
if (go == 1)
{
break;
}
}
go = 0;
}
}
function GoogleTranslate (text, from, to) {
var newScript = document.createElement('script');
var sourceText = escape(text);
newScript.type = 'text/javascript';
var APIKEY = 'my api key';
var source = 'https://www.googleapis.com/language/translate/v2?';
source += 'key=' + APIKEY;
source += '&source=' + from;
source += '&target=' + to;
source += '&callback=google_translation';
source += '&q=' + sourceText;
newScript.src = source;
console.log("sent");
// send the reuqest to google api
$('head')[0].appendChild(newScript);
}
// callback
function google_translation(response) {
g_response = response.data.translations[0].translatedText;
if (method == 0)
{
// replaces text in a given location (not for code shown)
g_where.val(g_response);
console.log("0");
}
if (method == 1)
{
// appends text in a given location
g_where.append(": " + g_response + "<br>");
console.log("1");
}
if (method == 2)
{
// sets variable to response
g_loop = g_response;
console.log("2");
}
go = 1;
console.log("translated");
}
var translate\u all=函数translate\u all(){
//将全局g_设置为此div的何处以附加图像
g#u where=$(“#g#u div”);
g_其中。追加(“
”);
//获取用户输入的文本
var a_text=$(“#精度_text”).val();
//api的翻译代码
var语言代码=[“en”、“ar”、“bg”、“ca”、“hr”、“cs”、“da”、“nl”、“et”、“fi”、“fr”、“de”、“el”、“ht”、“id”、“it”、“ko”、“lv”、“lt”、“ms”、“mt”、“no”、“fa”、“pl”、“pt”、“ro”、“ru”、“sl”、“sl”、“es”、“th”、“tr”、“uk”、“ur”、“vi”];
//将全局g_循环设置为用户输入的文本
g_循环=a_文本;
//开始循环
对于(变量i=1;i”);
控制台日志(“1”);
}
if(方法==2)
{
//将变量设置为响应
g_环=g_响应;
控制台日志(“2”);
}
go=1;
控制台日志(“翻译”);
}
您可以创建一系列承诺,这些承诺将按如下顺序运行:
myList.reduce((promise, item) => {
return promise.then(() => new Promise((resolve, reject) => {
// do whatever you need to do here
// resolve when finished with this iteration.
}))
}, Promise.resolve());
因此,假设您有一个类似于[1,2,3]
的列表,并且您给出了回调承诺。
使用此方法或多或少会转化为:
Promise.resolve()
.then(1 => function () { })
.then(2 => function () { })
.then(3 => function () { });
你好谢谢你的回复,但我还是不确定它到底是什么意思;我对承诺感到很不舒服。你介意再详细说明一下吗?(myList将在哪里定义?item定义在哪里?我是否在新承诺中解析?)抱歉,如果这些问题看起来很简单。基本上,承诺只是编写回调的另一种方式。这将创建一个按顺序执行的回调链