I want to get the comments from a YouTube video and do some further work with them. I started with the implementation example from the docs for "CommentThreads: list" and continued from there on.
Using a main function I want to call the execute function and use the response it should return. It should look kinda like the following:
function execute() {
return gapi.client.youtube.commentThreads.list({
"part": [
"snippet"
],
"fields":[
"items/snippet/topLevelComment/snippet(authorDisplayName,authorProfileImageUrl,publishedAt,textDisplay)"
],
"videoId": "XXXXX"
}).then(function(response) {
console.log(response.result);
},
function(err) {
console.error("Execute error", err);
});
}
function main(){
let response = execute();
console.log(response);
}
And the output in the console looks like this:
{
"Ca": 2,
"yb": null,
"Yj": null,
"Sn": null,
"KB": false,
"xw": false
}
Another way I tried to solve this is to not return gapi.client.youtube.commentThreads.list but the response in the successful promise function like so:
function execute() {
gapi.client.youtube.commentThreads.list({
"part": [
"snippet"
],
"fields":[
"items/snippet/topLevelComment/snippet(authorDisplayName,authorProfileImageUrl,publishedAt,textDisplay)"
],
"videoId": "XXXXX"
}).then(function(response) {
console.log(response.result);
return reponse.result;
},
function(err) {
console.error("Execute error", err);
});
}
But here I only get an undefined.
I am just learning JavaScript and the use of the API.
EDIT:
I should also add that the console.log(response.result); in the execute function does print the information I want. But as soon as I return it and want to use it in the main() function it changes.
The problem seems to that when using the gapi that it returns a promise that I want to return. Promised are not evaluated immediately which means that it continues to execute the following functions, returning a value that has no response yet.
I solved the issue by using the async/await functionality to work with promises, which seemed to be more understandable and elegant in my eyes. I also changed some variables to constants as they did not need to be non-constants. My result looks like the following:
await function execute() {
let response = await gapi.client.youtube.commentThreads.list({
"part": [
"snippet"
],
"fields":[
"items/snippet/topLevelComment/snippet(authorDisplayName,authorProfileImageUrl,publishedAt,textDisplay)"
],
"videoId": "XXXXX"
});
return response.result;
}
async function main(){
let response = await execute();
console.log(response);
}
The reason why we also have to use async and await in the main() function is that by definition async functions always return promises.
To learn more about async/await I found this article whose explanation I liked: https://javascript.info/async-await
They also have an article about promises: https://javascript.info/promise-basics