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Merge pull request #1578 from hrodward/patch-34

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@ -9,7 +9,7 @@ Let's see a simple example first, to grasp the syntax, and then review a real-li
Asynchronous iterators are similar to regular iterators, with a few syntactic differences. Asynchronous iterators are similar to regular iterators, with a few syntactic differences.
"Regular" iterable object, as described in the chapter <info:iterable>, look like this: A "regular" iterable object, as described in the chapter <info:iterable>, looks like this:
```js run ```js run
let range = { let range = {
@ -79,8 +79,10 @@ let range = {
// (automatically wrapped into a promise by async) // (automatically wrapped into a promise by async)
*/!* */!*
*!*
// can use await inside, do async stuff: // can use await inside, do async stuff:
await new Promise(resolve => setTimeout(resolve, 1000)); // (3) await new Promise(resolve => setTimeout(resolve, 1000)); // (3)
*/!*
if (this.current <= this.last) { if (this.current <= this.last) {
return { done: false, value: this.current++ }; return { done: false, value: this.current++ };
@ -267,7 +269,7 @@ So far we've seen simple examples, to gain basic understanding. Now let's review
There are many online services that deliver paginated data. For instance, when we need a list of users, a request returns a pre-defined count (e.g. 100 users) - "one page", and provides a URL to the next page. There are many online services that deliver paginated data. For instance, when we need a list of users, a request returns a pre-defined count (e.g. 100 users) - "one page", and provides a URL to the next page.
The pattern is very common, it's not about users, but just about anything. For instance, GitHub allows to retrieve commits in the same, paginated fashion: This pattern is very common. It's not about users, but just about anything. For instance, GitHub allows to retrieve commits in the same, paginated fashion:
- We should make a request to URL in the form `https://api.github.com/repos/<repo>/commits`. - We should make a request to URL in the form `https://api.github.com/repos/<repo>/commits`.
- It responds with a JSON of 30 commits, and also provides a link to the next page in the `Link` header. - It responds with a JSON of 30 commits, and also provides a link to the next page in the `Link` header.
@ -283,7 +285,7 @@ for await (let commit of fetchCommits(repo)) {
} }
``` ```
We'd like to make a function `fetchCommits(repo)` that gets commits for us, making requests whenever needed. And let it care about all pagination stuff, for us it'll be a simple `for await..of`. We'd like to make a function `fetchCommits(repo)` that gets commits for us, making requests whenever needed. And let it care about all pagination stuff. For us it'll be a simple `for await..of`.
With async generators that's pretty easy to implement: With async generators that's pretty easy to implement: