Get the default iterator or async iterator for an Iterable.
MIT License
Get the default iterator or async iterator for an iterable or async iterable
Reduce the boilerplate of extracting the iterator from an object when you don't know if the object is an (async) iterable or already an (async) iterator.
npm install get-iterator
import { getIterator } from 'get-iterator'
const input = [1, 2, 3]
const it = getIterator(input)
console.log(it.next()) // { done: false, value: 1 }
console.log(it.next()) // { done: false, value: 2 }
console.log(it.next()) // { done: false, value: 3 }
console.log(it.next()) // { done: true, value: undefined }
Regular iterator from iterable:
import { getIterator } from 'get-iterator'
const input = [1, 2, 3]
const iterable = {
[Symbol.iterator] () {
let i = 0
return {
next () {
const value = input[i++]
return { done: !value, value }
}
}
}
}
const it = getIterator(input)
console.log(it.next()) // { done: false, value: 1 }
console.log(it.next()) // { done: false, value: 2 }
console.log(it.next()) // { done: false, value: 3 }
console.log(it.next()) // { done: true, value: undefined }
Async iterator from iterable:
import { getIterator } from 'get-iterator'
const input = [1, 2, 3]
const iterable = {
[Symbol.asyncIterator] () {
let i = 0
return {
async next () {
const value = await new Promise((resolve, reject) => {
setTimeout(() => resolve(input[i++]), 10)
})
return { done: !value, value }
}
}
}
}
const it = getIterator(iterable)
console.log(await it.next()) // { done: false, value: 1 }
console.log(await it.next()) // { done: false, value: 2 }
console.log(await it.next()) // { done: false, value: 3 }
console.log(await it.next()) // { done: true, value: undefined }
Already an iterator (probably):
import { getIterator } from 'get-iterator'
const input = [1, 2, 3]
let i = 0
const iterator = {
next () {
const value = input[i++]
return { done: !value, value }
}
}
const it = getIterator(iterator)
console.log(it.next()) // { done: false, value: 1 }
console.log(it.next()) // { done: false, value: 2 }
console.log(it.next()) // { done: false, value: 3 }
console.log(it.next()) // { done: true, value: undefined }
import { getIterator } from 'get-iterator'
getIterator(obj)
Get the default iterator or async iterator for an Iterable. If obj
is already an iterator (i.e. has a next
function) return it, since it's probably already an iterator.
This function will throw if obj
is not an iterable or iterator.
Name | Type | Description |
---|---|---|
obj |
Iterable |Iterator
|
The object to extract the iterator from (may be an iterator already). |
Type | Description |
---|---|
Iterator |
The result of calling obj[Symbol.iterator]() or obj[Symbol.asyncIterator]() or simply the passed obj if it is already an iterator. |
Feel free to dive in! Open an issue or submit PRs.
MIT © Alan Shaw