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如何调用带有promise的函数?

promise javascript

Martin AJ · 技术社区 · 6 年前

var gblink = require('./getbloglinks');

new Promise(function (resolve, reject) {
     var getLinks = gblink.getBlogLinks("www.example.com");
     resolve(getLinks);

}).then(function (data) {
     console.log("here");
     console.log(data);
     return false;
})

gblink.getBlogLinks() 是一个函数,它获取一个URL并返回该页中的所有链接 .当我运行代码时,立即 console.log("here"); console.log(data); 将打印为 undefined

getBlogLinks() 返回?

gblink.getBloglinks()。

这是

const NN = require('nightmare');

exports.getBlogLinks = function (data){

    const n = NN({show:true});

    n.goto(data)

    .evaluate(() => {

        var data = document.querySelectorAll("a[target='_blank']");

        arr = [];
        i=0;
        Array.from(data).forEach( function(x){
            arr[i] = x.href;
            i++;
        });
        return arr;
    })
    .then((data) => {
        return n.end(data);


    })
}

2 回复 | 直到 6 年前

Sandeep Gupta 6 年前

getBlogLinks

const NN = require('nightmare');

exports.getBlogLinks = function (data){

    const n = NN({show:true});

    return n.goto(data)

        .evaluate(() => {

            var data = document.querySelectorAll("a[target='_blank']");

            arr = [];
            i=0;
            Array.from(data).forEach( function(x){
                arr[i] = x.href;
                i++;
            });
            return arr;
        })
        .then((data) => {
            n.end(data);
            return data;
        })
};

var gblink = require('./getbloglinks');

new Promise(function (resolve, reject) {
     var getLinks = gblink.getBlogLinks("www.example.com");
     console.log(getLinks);//========= Here You will get Pending promise =========
     resolve(getLinks);

}).then(function (data) {
     console.log("here");
     console.log(data);//========= Here You will get the array=========
     return false;
})

编辑2:

var gblink = require('./getbloglinks');

/*
new Promise(function (resolve, reject) {
    var getLinks = gblink.getBlogLinks("www.example.com");
    console.log(getLinks);//========= Here You will get Pending promise =========
    resolve(getLinks);

})*/
//Below is recommended way to chain the promise, avoid promise constructor, if not needed
gblink.getBlogLinks("www.example.com")
    .then(function (data) {
        console.log("here");
        console.log(data);//========= Here You will get the array=========
        return false;
    })

Aseem Upadhyay 6 年前

getBlogLinks() 是在您的开发范围内实现的功能。

getBlogLInks() 只有在有响应时才会返回响应。但你称之为同步。

getBlogLinks 需要有一个承诺。

getBlogLinks(data) {
  return new Promise( function(resolve,reject) {
      ....all your function code
      .then(data) {
          resolve(data); 
       }
  });
  }

getBlogLinks().then