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flatten.ts
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flatten.ts
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import { IEnumerable, IFlatten } from "../../types"
import { BasicEnumerable } from "../BasicEnumerable"
type FlattenFunc = {
/**
* Flattens an iterable
* @param source Iterable to flatten
* @param shallow When false - recurses the iterable types
*/
<TSource>(
source: IFlatten<TSource>, shallow?: false): IEnumerable<TSource>
/**
* Flattens an iterable
* @param source Iterable to flatten
* @param shallow When false - recurses the iterable types
*/
<TSource>(
source: IFlatten<TSource>, shallow: true): IEnumerable<TSource | Iterable<TSource>>
}
export const flatten: FlattenFunc = <TSource>(
source: IFlatten<TSource>, shallow?: boolean): IEnumerable<TSource | Iterable<TSource>> => {
// eslint-disable-next-line no-shadow
function* iterator(source: Iterable<any>): IterableIterator<TSource | Iterable<TSource>> {
for (const item of source) {
// JS string is an Iterable.
// We exclude it from being flattened
// eslint-disable-next-line @typescript-eslint/no-unsafe-member-access
if (item[Symbol.iterator] !== undefined && typeof item !== "string") {
// eslint-disable-next-line @typescript-eslint/no-unsafe-argument
yield* shallow ? item : iterator(item)
} else {
yield item
}
}
}
return new BasicEnumerable(() => iterator(source))
}