Develop Reference

Fetch text from url then stringify it

So i have just started to learn javascript today and i'm trying to fetch text from a url and then split and stringify it using josn.
Then i'm trying to pick a random proxy from the stringify json and log it in my self invoking function but it logs as undefined and i can't workout what i'm doing wrong and i was hoping maybe someone could tell me what i'm doing wrong.
My code:
const doFetch = async () => {
try {
let proxies = [];
let socks = await fetch("https://raw.githubusercontent.com/TheSpeedX/PROXY-List/master/socks4.txt");
let response = await socks.text();
let list = response.toString().split('\n');
for (let i = 0; i < list.length; i++) {
let splitText = list[i].split(':');
proxies.push(JSON.stringify({'type': 'socks4', 'ip': splitText[0], 'port': splitText[1]}));
}
return proxies
} catch (error) {
console.log('fetch error:', error.message);
}
}
(async () => {
let proxies = await doFetch();
let proxie = proxies[Math.floor(Math.random() * proxies.length)];
console.log(proxie); // logs fine
console.log(proxie.type, proxie.ip, proxie.port); // logs as undefined
})();

proxie.type, proxie.ip, proxie.port are undefined because proxie is a string and not an object. Rewrite your code in this way:
(async () => {
let proxies = await doFetch();
let proxie = proxies[Math.floor(Math.random() * proxies.length)];
console.log(proxie); // logs fine
let proxieObj = JSON.parse(proxie);
console.log(proxieObj.type, proxieObj.ip, proxieObj.port);
})();

There are 2 identical receive values ​from a promise: in one case it works, in another it gives an TypeError: x is not a function

I use the element search in my autotest and take the name from the list. My code works, everything is fine. But in autotest I use this code several times. Therefore, I decided to put it into a function and call it when I need to.
Code operates:
await driver.wait(until.elementLocated(By.className("item")), 20000);
let findItems1 = await driver.findElements(By.className("item"));
let items1 = findItems1.map(async elem => await elem.getText());
await Promise.all(items1);
let currentItem1 = findItems1[findItems1.length - 1];
await currentItem1.click();
currentName = await currentItem1.getText(); // This string operates
await Promise.all(currentName)
console.log(currentName)
I infer the value of the variable from the function in which the promise lies. I can click on this item. But when I want to get a text value from a promise, the string "currentName = await currentItem1.getText()" throws an error. Although in my first code this line works. I don’t understand what could be the reason.
Code doesn't operate:
async function findCurrentItem(){
await driver.wait(until.elementLocated(By.className("item")), 20000);
let findItems = await driver.findElements(By.className("item"));
let items = findItems.map(async elem => await elem.getText());
await Promise.all(items);
let currentItem = findItems[findItems.length - 1];
return currentItem;
}
let current = findCurrentItem();
await currentItem1.click();
console.log(current, 1) // console displays promise
let currentName = await current.getText(); // This string doesn't operate
await Promise.all(currentName)
console.log(currentName, 2) // console displays error
Error:
TypeError: currentItem.getText is not a function
What can I do?

You made findCurrentItem async function but don't await its result when using it.
Change to let current = await findCurrentItem();

How can I access and use a return value from a do while loop?

I am trying to access return data from a do while loop, but I am unable to do so.
I have stored the information in a new variable (starships) and then returned this variable, but it says starships is not defined. I see that this may be a scoping issue, how can I resolve this?
async function getData() {
const allResults = [];
let url = 'https://swapi.co/api/starships/';
do {
const res = await fetch(url);
const data = await res.json();
url = data.next;
allResults.push(...data.results);
console.log(allResults);
} while (url !== null)
let starships = allResults;
return starships;
}
console.log(starships);

You need to get the value which is returned from getData. The most obvious way to do this with the async/await structure you have is to just await it:
async function getData() {
const allResults = [];
let url = 'https://swapi.co/api/starships/';
do {
const res = await fetch(url);
const data = await res.json();
url = data.next;
allResults.push(...data.results);
console.log(allResults);
} while (url !== null)
let starships = allResults;
return starships;
}
async function doTheDo() {
const test = await getData();
console.dir(test);
}
doTheDo();

you can do this. starships is defined inside the loop. Additionally, you are not calling getData() function. You can store that return value like this
const result = await getData();
console.log(result);
or you can directly print like this. console.log(await getData())
async function getData() {
const allResults = [];
let url = 'https://swapi.co/api/starships/';
do {
const res = await fetch(url);
const data = await res.json();
url = data.next;
allResults.push(...data.results);
console.log(allResults);
} while (url !== null)
return allResults;
}
console.log(await getData());

Async functions return a promise, which means you have to access the return value with a .then().
However, you have another problem: starships is in the scope of the function getData() which you have defined, but not called.
So first lets call your function:
async function getData() {
const allResults = [];
// do stuff
let starships = allResults;
return starships;
}
console.log(getData());
Now you will see that your log value is [object Promise] which isn't so helpful in its current form. This is because the code outside the async function is running synchronously, which means we don't have the value yet, just a promise to maybe return the value sometime in the future.
So now we need to access the promise asynchronously using the .then() like so:
async function getData() {
const allResults = [];
// do stuff
let starships = allResults;
return starships;
}
getData().then(starships => {
console.log(starships);
});
Now you should see the info you were expecting to be logged.
You can also save promise to a variable and pass it around and access it elsewhere in your code like so:
async function getData() {
const allResults = [];
// do stuff
let starships = allResults;
return starships;
}
let starshipPromise = getData();
// time & code passes...
starshipPromise.then(starship => {
console.log(starship);
}).catch(error => {
// handle error
});
And don't forget to catch your rejected promises!
See the MDN docs on Async functions: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/async_function
And if you need more info on promises, go here: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise

angular 6 wait post response

var data2 = { data1Id: 0 };
postData(){
this._service1.save(data1).subscribe(res => {
this.data2.data1Id = res.Data.Id; //res.Data.Id has valid data
});
this._service2.save(data2).subscribe(res => {
console.log(this.data2.data1Id); //"this.data2.data1Id = 0" can't get value from service1
});
}
how can i get data from the first service or some function take me resolve problem run call service sequence. thank for watching !

Using async/await is perfect for your situation. It will help you to make your code more readable and make abstraction of the async part thanks to the await keyword
aync post(){
const res1 = await this._service1.save(this.data1).toPromise();
const res2 = await this._service2.save(res1).toPromise();
console.log('here is my data 2 ' + res2);
return 'what you want, can be res1 or res2 or a string';
}
How to call it ?
this.myService.post().then( (whatYouWanted) => {
console.log(whatYouWanted); // what you want, can be res1 or res2 or a string
});

this._service1.save(data1).flatMap(res => {
this.data2.data1Id = res.Data.Id; //res.Data.Id has valid data
return this._service2.save(data2);
}).subscribe(res => {
console.log(this.data2.data1Id); //"this.data2.data1Id = 0" can't get value from service1
});
You can use flatMap and return the second observable to chain them.
Documentation: http://reactivex.io/documentation/operators/flatmap.html

Promise/async-await with mongoose, returning empty array

The console in the end returns empty array.
The console runs before ids.map function finishes
var ids = [];
var allLync = []
var user = await User.findOne(args.user)
ids.push(user._id)
user.following.map(x => {
ids.push(x)
})
ids.map(async x => {
var lync = await Lync.find({ "author": x })
lync.map(u => {
allLync.push[u]
})
})
console.log(allLync)
What am I doing wrong?

The .map code isn't awaited, so the console.log happens before the mapping happens.
If you want to wait for a map - you can use Promise.all with await:
var ids = [];
var allLync = []
var user = await User.findOne(args.user)
ids.push(user._id)
user.following.map(x => {
ids.push(x)
})
// note the await
await Promise.all(ids.map(async x => {
var lync = await Lync.find({ "author": x })
lync.map(u => {
allLync.push(u); // you had a typo there
})
}));
console.log(allLync)
Note though since you're using .map you can shorten the code significantly:
const user = await User.findOne(args.user)
const ids = users.following.concat(user._id);
const allLync = await Promise.all(ids.map(id => Lync.find({"author": x })));
console.log(allLync);

Promise.map() is now an option that would be a tiny bit more succinct option, if you don't mind using bluebird.
It could look something like:
const user = await User.findOne(args.user);
const ids = users.following.concat(user._id);
const allLync = await Promise.map(ids, (id => Lync.find({"author": x })));
console.log(allLync);
http://bluebirdjs.com/docs/api/promise.map.html. I have really enjoyed using it.