Mixing
How can I call a function with promise?
How can I call a function with promise?
Here is my code:
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() is a function which gets a URL and returns all links in that page (after a short time). When I run my code, immediately console.log("here"); will be printed and then console.log(data); will be printed as undefined.
gblink.getBlogLinks()
console.log("here");
console.log(data);
undefined
Anyway how can I make that promise waiting until the result of getBlogLinks() returns?
getBlogLinks()
Noted that when I call gblink.getBlogLinks() function manually, it works as well, it just takes a while and all I need to do now is implementing a waiting system for that function.
gblink.getBlogLinks()
Here is gblink.getBlogLinks():
gblink.getBlogLinks()
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);
})
}
is gblink.getBlogLinks() itself a promise ? then you have to implement then() on it.
– codeteq
Jun 29 at 8:47
@codeteq No it is not promise. it is nightmare.
– Martin AJ
Jun 29 at 8:48
can you share the implementation of getbloglinks()?
– Aseem Upadhyay
Jun 29 at 8:49
@AseemUpadhyay Sure ..
– Martin AJ
Jun 29 at 8:49
2 Answers
2
getBlogLinks is not returning the promise. Doing that should solve the problem.
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;
})
};
Edited:
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;
})
Edited2:
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;
})
Thank you so much .. it worked
– Martin AJ
Jun 29 at 8:58
@MartinAJ Welcome :)
– dasfdsa
Jun 29 at 8:58
As a note, your solution doesn't work totally. It will work if I write
console.log(data) in the .then() block of getBlogLinks function. But still getBlogLinks function doesn't return the result to the promise in the main page.– Martin AJ
Jun 29 at 9:16
console.log(data)
.then()
getBlogLinks
getBlogLinks
@MartinAJ Can you
console.log(getLinks) and check if its a promise of not?– dasfdsa
Jun 29 at 9:19
console.log(getLinks)
In where should I write
console.log(getLinks)? in the resolve block on the promise?– Martin AJ
Jun 29 at 9:20
console.log(getLinks)
resolve
I am assuming that getBlogLinks() is a function implemented in your scope of development.
getBlogLinks()
So, what is happening, in your current code of getBlogLInks() the response is getting returned only when there is a response. But the way you call it, it's synchronous.
getBlogLInks()
Your getBlogLinks need to be wrapped in a promise.
getBlogLinks
getBlogLinks(data) {
return new Promise( function(resolve,reject) {
....all your function code
.then(data) {
resolve(data);
}
});
}
then use getBlogLinks().then and you will have your answer
getBlogLinks().then
Hey Aseem. I think this solution may not work.
resolve(data) in your code will not resolve the right data but rather, the data received by getBlogLinks as argument.– dasfdsa
Jun 29 at 9:07
resolve(data)
data
data
getBlogLinks
oh that might be a misunderstanding let me correct it
– Aseem Upadhyay
Jun 29 at 9:30
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You need to call resolve in gblink.getBlogLinks callback
– anttud
Jun 29 at 8:47