<E, R>(self: Stream<string, E, R>): Effect.Effect<string, E, R>Concatenates all emitted strings into a single string.
Example (Joining strings from a stream)
import { Console, Effect, Stream } from "effect"
const stream = Stream.make("Hello", " ", "World", "!")
const program = Effect.gen(function*() {
const text = yield* Stream.mkString(stream)
yield* Console.log(text)
})
Effect.runPromise(program)
// Hello World!destructors
Source effect/Stream.ts:110626 lines
export const const mkString: <E, R>(
self: Stream<string, E, R>
) => Effect.Effect<string, E, R>
Concatenates all emitted strings into a single string.
Example (Joining strings from a stream)
import { Console, Effect, Stream } from "effect"
const stream = Stream.make("Hello", " ", "World", "!")
const program = Effect.gen(function*() {
const text = yield* Stream.mkString(stream)
yield* Console.log(text)
})
Effect.runPromise(program)
// Hello World!
mkString = <function (type parameter) E in <E, R>(self: Stream<string, E, R>): Effect.Effect<string, E, R>E, function (type parameter) R in <E, R>(self: Stream<string, E, R>): Effect.Effect<string, E, R>R>(self: Stream<string, E, R>(parameter) self: {
channel: Channel.Channel<Arr.NonEmptyReadonlyArray<A>, E, void, unknown, unknown, unknown, R>;
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
}
interface Stream<out A, out E = never, out R = never>A Stream<A, E, R> describes a program that can emit many A values, fail
with E, and require R.
Details
Streams are pull-based with backpressure and emit chunks to amortize effect
evaluation. They support monadic composition and error handling similar to
Effect, adapted for multiple values.
Example (Creating and consuming streams)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
yield* Stream.make(1, 2, 3).pipe(
Stream.map((n) => n * 2),
Stream.runForEach((n) => Console.log(n))
)
})
Effect.runPromise(program)
// Output:
// 2
// 4
// 6
Stream<string, function (type parameter) E in <E, R>(self: Stream<string, E, R>): Effect.Effect<string, E, R>E, function (type parameter) R in <E, R>(self: Stream<string, E, R>): Effect.Effect<string, E, R>R>): import EffectEffect.type Effect.Effect = /*unresolved*/ anyEffect<string, function (type parameter) E in <E, R>(self: Stream<string, E, R>): Effect.Effect<string, E, R>E, function (type parameter) R in <E, R>(self: Stream<string, E, R>): Effect.Effect<string, E, R>R> =>
import ChannelChannel.runFold(
self: Stream<string, E, R>(parameter) self: {
channel: Channel.Channel<Arr.NonEmptyReadonlyArray<A>, E, void, unknown, unknown, unknown, R>;
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
}
Stream<out A, out E = never, out R = never>.channel: Channel.Channel<Arr.NonEmptyReadonlyArray<A>, E, void, unknown, unknown, unknown, R>(property) Stream<out A, out E = never, out R = never>.channel: {
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
}
acc: anyacc, chunk: any(parameter) chunk: {
0: string;
length: number;
toString: () => string;
toLocaleString: { (): string; (locales: string | string[], options?: Intl.NumberFormatOptions & Intl.DateTimeFormatOptions): string };
concat: { (...items: Array<ConcatArray<string>>): Array<string>; (...items: Array<string | ConcatArray<string>>): Array<string> };
join: (separator?: string) => string;
slice: (start?: number, end?: number) => Array<string>;
indexOf: (searchElement: string, fromIndex?: number) => number;
lastIndexOf: (searchElement: string, fromIndex?: number) => number;
every: { (predicate: (value: string, index: number, array: ReadonlyArray<string>) => value is S, thisArg?: any): this is readonly S[]; (predicate: (value: string, index: number, array: ReadonlyArray<string>) => unknown, thisArg?: any): boolean };
some: (predicate: (value: string, index: number, array: ReadonlyArray<string>) => unknown, thisArg?: any) => boolean;
forEach: (callbackfn: (value: string, index: number, array: ReadonlyArray<string>) => void, thisArg?: any) => void;
map: (callbackfn: (value: string, index: number, array: ReadonlyArray<string>) => U, thisArg?: any) => Array<U>;
filter: { (predicate: (value: string, index: number, array: ReadonlyArray<string>) => value is S, thisArg?: any): Array<S>; (predicate: (value: string, index: number, array: ReadonlyArray<string>) => unknown, thisArg?: any): Array<string> };
reduce: { (callbackfn: (previousValue: string, currentValue: string, currentIndex: number, array: ReadonlyArray<string>) => string): string; (callbackfn: (previousValue: string, currentValue: string, currentIndex: number, array: ReadonlyArray<stri…;
reduceRight: { (callbackfn: (previousValue: string, currentValue: string, currentIndex: number, array: ReadonlyArray<string>) => string): string; (callbackfn: (previousValue: string, currentValue: string, currentIndex: number, array: ReadonlyArray<stri…;
find: { (predicate: (value: string, index: number, obj: ReadonlyArray<string>) => value is S, thisArg?: any): S | undefined; (predicate: (value: string, index: number, obj: ReadonlyArray<string>) => unknown, thisArg?: any): string | undefined };
findIndex: (predicate: (value: string, index: number, obj: ReadonlyArray<string>) => unknown, thisArg?: any) => number;
entries: () => ArrayIterator<[number, string]>;
keys: () => ArrayIterator<number>;
values: () => ArrayIterator<string>;
includes: (searchElement: string, fromIndex?: number) => boolean;
flatMap: (callback: (this: This, value: string, index: number, array: Array<string>) => U | ReadonlyArray<U>, thisArg?: This | undefined) => Array<U>;
flat: (this: A, depth?: D | undefined) => Array<FlatArray<A, D>>;
at: (index: number) => string | undefined;
findLast: { (predicate: (value: string, index: number, array: ReadonlyArray<string>) => value is S, thisArg?: any): S | undefined; (predicate: (value: string, index: number, array: ReadonlyArray<string>) => unknown, thisArg?: any): string | undefine…;
findLastIndex: (predicate: (value: string, index: number, array: ReadonlyArray<string>) => unknown, thisArg?: any) => number;
toReversed: () => Array<string>;
toSorted: (compareFn?: ((a: string, b: string) => number) | undefined) => Array<string>;
toSpliced: { (start: number, deleteCount: number, ...items: Array<string>): Array<string>; (start: number, deleteCount?: number): Array<string> };
with: (index: number, value: string) => Array<string>;
}
acc: anyacc + chunk: any(parameter) chunk: {
0: string;
length: number;
toString: () => string;
toLocaleString: { (): string; (locales: string | string[], options?: Intl.NumberFormatOptions & Intl.DateTimeFormatOptions): string };
concat: { (...items: Array<ConcatArray<string>>): Array<string>; (...items: Array<string | ConcatArray<string>>): Array<string> };
join: (separator?: string) => string;
slice: (start?: number, end?: number) => Array<string>;
indexOf: (searchElement: string, fromIndex?: number) => number;
lastIndexOf: (searchElement: string, fromIndex?: number) => number;
every: { (predicate: (value: string, index: number, array: ReadonlyArray<string>) => value is S, thisArg?: any): this is readonly S[]; (predicate: (value: string, index: number, array: ReadonlyArray<string>) => unknown, thisArg?: any): boolean };
some: (predicate: (value: string, index: number, array: ReadonlyArray<string>) => unknown, thisArg?: any) => boolean;
forEach: (callbackfn: (value: string, index: number, array: ReadonlyArray<string>) => void, thisArg?: any) => void;
map: (callbackfn: (value: string, index: number, array: ReadonlyArray<string>) => U, thisArg?: any) => Array<U>;
filter: { (predicate: (value: string, index: number, array: ReadonlyArray<string>) => value is S, thisArg?: any): Array<S>; (predicate: (value: string, index: number, array: ReadonlyArray<string>) => unknown, thisArg?: any): Array<string> };
reduce: { (callbackfn: (previousValue: string, currentValue: string, currentIndex: number, array: ReadonlyArray<string>) => string): string; (callbackfn: (previousValue: string, currentValue: string, currentIndex: number, array: ReadonlyArray<stri…;
reduceRight: { (callbackfn: (previousValue: string, currentValue: string, currentIndex: number, array: ReadonlyArray<string>) => string): string; (callbackfn: (previousValue: string, currentValue: string, currentIndex: number, array: ReadonlyArray<stri…;
find: { (predicate: (value: string, index: number, obj: ReadonlyArray<string>) => value is S, thisArg?: any): S | undefined; (predicate: (value: string, index: number, obj: ReadonlyArray<string>) => unknown, thisArg?: any): string | undefined };
findIndex: (predicate: (value: string, index: number, obj: ReadonlyArray<string>) => unknown, thisArg?: any) => number;
entries: () => ArrayIterator<[number, string]>;
keys: () => ArrayIterator<number>;
values: () => ArrayIterator<string>;
includes: (searchElement: string, fromIndex?: number) => boolean;
flatMap: (callback: (this: This, value: string, index: number, array: Array<string>) => U | ReadonlyArray<U>, thisArg?: This | undefined) => Array<U>;
flat: (this: A, depth?: D | undefined) => Array<FlatArray<A, D>>;
at: (index: number) => string | undefined;
findLast: { (predicate: (value: string, index: number, array: ReadonlyArray<string>) => value is S, thisArg?: any): S | undefined; (predicate: (value: string, index: number, array: ReadonlyArray<string>) => unknown, thisArg?: any): string | undefine…;
findLastIndex: (predicate: (value: string, index: number, array: ReadonlyArray<string>) => unknown, thisArg?: any) => number;
toReversed: () => Array<string>;
toSorted: (compareFn?: ((a: string, b: string) => number) | undefined) => Array<string>;
toSpliced: { (start: number, deleteCount: number, ...items: Array<string>): Array<string>; (start: number, deleteCount?: number): Array<string> };
with: (index: number, value: string) => Array<string>;
}