如何实现此功能 - nodejs [英] How to Promisify this function - nodejs

问题描述

我有一个需要返回承诺的ajax调用。功能如下

I have an ajax call which needs to return a promise. The function is as follows

client.tickets.create(ticket,  function(err, req, result) {
  if (err) {    
    logger.error(err);

    return false;
  }

  return JSON.stringify(result);
});

我必须等待此功能执行才能执行下一个操作。我怎样才能宣传这个功能？

I have to wait for this function to execute before I can perform the next action. How can I promisify this function ?

我尝试了以下内容并且它给了我一个错误说无法调用方法然后是未定义的：

I tried the following and it gave me an error saying Cannot call method then of undefined:

return client.tickets.create(ticket).then(function(result){
    return JSON.stringify(result);
},function(err){
    logger.error(err);
    return false;
});

推荐答案

您有错误，因为 create（）不是Promise。宣传异步功能非常简单（nodejs现在有内置的Promise支持）：

You have the error because create() is not a Promise. Promisifying an async function is quite easy (nodejs has a built-in Promise support nowadays):

function createTicket(ticket) {
    // 1 - Create a new Promise
    return new Promise(function (resolve, reject) {
        // 2 - Copy-paste your code inside this function
        client.tickets.create(ticket, function (err, req, result) {
            // 3 - in your async function's callback
            // replace return by reject (for the errors) and resolve (for the results)
            if (err) {
                reject(err);
            } else {
                resolve(JSON.stringify(result));
            }
        });
    });
}

// 4 - consume your promise with then() (resolved promise) and catch (rejected promise)
createTicket(ticket).then(function (result) {
    // deal with result here
}).catch(function (err) {
    // deal with error here
});

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