Class StreamImpl<S, T>

The default implementation of Stream works with two input functions:

The first function creates the initial state of an iteration.
The second function gets the current state as argument and returns an IteratorResult.

Type Parameters

Hierarchy (view full)

StreamImpl
- TreeStreamImpl

Implements

Stream<T>

Index

Constructors

constructor

Properties

nextFn startFn

Constructors

constructor

new StreamImpl<S, T>(startFn, nextFn): StreamImpl<S, T>
Type Parameters
- S
- T
Parameters
- startFn: (() => S)
 - - (): S
 - Returns S
- nextFn: ((state: S) => IteratorResult<T, undefined>)
 - - (state): IteratorResult<T, undefined>
 - Parameters
 state: S
 Returns IteratorResult<T, undefined>
Returns StreamImpl<S, T>
- Defined in packages/langium/src/utils/stream.ts:265

Properties

`Protected` `Readonly`nextFn

nextFn: ((state: S) => IteratorResult<T, any>)

`Protected` `Readonly`startFn

startFn: (() => S)

Methods

[iterator]

[iterator](): Iterator<T, any, undefined>
Returns Iterator<T, any, undefined>
Implementation of Stream.[iterator]
- Defined in packages/langium/src/utils/stream.ts:279

concat

concat<T2>(other): Stream<T | T2>
Combines two streams by returning a new stream that yields all elements of this stream and the other stream.
Type Parameters
- T2
Parameters
- other: Iterable<T2>
 Stream to be concatenated with this one.
Returns Stream<T | T2>
Implementation of Stream.concat
- Defined in packages/langium/src/utils/stream.ts:328

count

count(): number
Determines the number of elements in this stream.

Returns number
Implementation of Stream.count
- Defined in packages/langium/src/utils/stream.ts:288

distinct

distinct<Key>(by?): Stream<T>
Returns a stream containing only the distinct elements from this stream. Equality is determined with the same rules as a standard Set.
Type Parameters
- Key = T
Parameters
- Optionalby: ((element: T) => Key)
 A function returning the key used to check equality with a previous stream element. If omitted, the stream elements themselves are used for comparison.
 - - (element): Key
 - Parameters
 element: T
 Returns Key
Returns Stream<T>
Implementation of Stream.distinct
- Defined in packages/langium/src/utils/stream.ts:647

every

every(predicate): this is Stream & StreamImpl<S, T>
Determines whether all members of the stream satisfy the specified test.
Type Parameters
- U
Parameters
- predicate: ((value: T) => value is U)
 This method calls the predicate function for each element in the stream until the predicate returns a value which is coercible to the Boolean value false, or until the end of the stream.
 - - (value): value is U
 - Parameters
 value: T
 Returns value is U
Returns this is Stream & StreamImpl<S, T>
Implementation of Stream.every
- Defined in packages/langium/src/utils/stream.ts:396
every(predicate): boolean
Determines whether all members of the stream satisfy the specified test.
Parameters
- predicate: ((value: T) => unknown)
  This method calls the predicate function for each element in the stream until the predicate returns a value which is coercible to the Boolean value false, or until the end of the stream.
  - - (value): unknown
    - Parameters
      value: T
      Returns unknown
Returns boolean
Implementation of Stream.every
- Defined in packages/langium/src/utils/stream.ts:397

exclude

exclude<Key>(other, key?): Stream<T>
Returns a stream that contains all elements that don't exist in the other iterable. Equality is determined with the same rules as a standard Set.
Type Parameters
- Key = T
Parameters
- other: Iterable<T>
 The elements that should be exluded from this stream.
- Optionalkey: ((element: T) => Key)
 A function returning the key used to check quality. If omitted, the stream elements themselves are used for comparison.
 - - (element): Key
 - Parameters
 element: T
 Returns Key
Returns Stream<T>
Implementation of Stream.exclude
- Defined in packages/langium/src/utils/stream.ts:667

filter

filter(predicate): Stream & StreamImpl<S, T>
Returns the elements of the stream that meet the condition specified in a callback function. The function is called when the resulting stream elements are actually accessed, so accessing the resulting stream multiple times means the function is also called multiple times for each element of the stream.
Type Parameters
- U
Parameters
- predicate: ((value: T) => value is U)
 Lazily evaluated function checking a condition on stream elements.
 - - (value): value is U
 - Parameters
 value: T
 Returns value is U
Returns Stream & StreamImpl<S, T>
Implementation of Stream.filter
- Defined in packages/langium/src/utils/stream.ts:448
filter(predicate): Stream<T> & StreamImpl<S, T>
Returns the elements of the stream that meet the condition specified in a callback function. The function is called when the resulting stream elements are actually accessed, so accessing the resulting stream multiple times means the function is also called multiple times for each element of the stream.
Parameters
- predicate: ((value: T) => unknown)
 Lazily evaluated function checking a condition on stream elements.
 - - (value): unknown
 - Parameters
 value: T
 Returns unknown
Returns Stream<T> & StreamImpl<S, T>
Implementation of Stream.filter
- Defined in packages/langium/src/utils/stream.ts:449

find

find<S>(predicate): undefined | S
Returns the value of the first element in the stream that meets the condition, or undefined if there is no such element.
Type Parameters
- S
Parameters
- predicate: ((value: T) => value is S)
  This method calls predicate once for each element of the stream, in ascending order, until it finds one where predicate returns a value which is coercible to the Boolean value true.
  - - (value): value is S
    - Parameters
      value: T
      Returns value is S
Returns undefined | S
Implementation of Stream.find
- Defined in packages/langium/src/utils/stream.ts:505
find(predicate): undefined | T
Returns the value of the first element in the stream that meets the condition, or undefined if there is no such element.
Parameters
- predicate: ((value: T) => unknown)
  This method calls predicate once for each element of the stream, in ascending order, until it finds one where predicate returns a value which is coercible to the Boolean value true.
  - - (value): unknown
    - Parameters
      value: T
      Returns unknown
Returns undefined | T
Implementation of Stream.find
- Defined in packages/langium/src/utils/stream.ts:506

findIndex

findIndex(predicate): number
Returns the index of the first element in the stream that meets the condition, or -1 if there is no such element.
Parameters
- predicate: ((value: T) => unknown)
  This method calls predicate once for each element of the stream, in ascending order, until it finds one where predicate returns a value which is coercible to the Boolean value true.
  - - (value): unknown
    - Parameters
      value: T
      Returns unknown
Returns number
Implementation of Stream.findIndex
- Defined in packages/langium/src/utils/stream.ts:519

flat

flat<D>(depth?): FlatStream<T, D>
Returns a new stream with all sub-stream or sub-array elements concatenated into it recursively up to the specified depth.
Type Parameters
- D extends number = 1
Parameters
- Optionaldepth: D
 The maximum recursion depth. Defaults to 1.
Returns FlatStream<T, D>
Implementation of Stream.flat
- Defined in packages/langium/src/utils/stream.ts:574

flatMap

flatMap(callbackfn): Stream
Calls a defined callback function on each element of the stream and then flattens the result into a new stream. This is identical to a map followed by flat with depth 1.
Type Parameters
- U
Parameters
- callbackfn: ((value: T) => U | Iterable)
 Lazily evaluated function mapping stream elements.
 - - (value): U | Iterable
 - Parameters
 value: T
 Returns U | Iterable
Returns Stream
Implementation of Stream.flatMap
- Defined in packages/langium/src/utils/stream.ts:545

forEach

forEach(callbackfn): void
Performs the specified action for each element in the stream.
Parameters
- callbackfn: ((value: T, index: number) => void)
  Function called once for each element in the stream.
  - - (value, index): void
    - Parameters
      value: T
      index: number
      Returns void
Returns void
Implementation of Stream.forEach
- Defined in packages/langium/src/utils/stream.ts:422

head

head(): undefined | T
Returns the first element in the stream, or undefined if the stream is empty.

Returns undefined | T
Implementation of Stream.head
- Defined in packages/langium/src/utils/stream.ts:609

includes

includes(searchElement): boolean
Determines whether the stream includes a certain element, returning true or false as appropriate.
Parameters
- searchElement: T
  The element to search for.
Returns boolean
Implementation of Stream.includes
- Defined in packages/langium/src/utils/stream.ts:533

indexOf

indexOf(searchElement, fromIndex?): number
Returns the index of the first occurrence of a value in the stream, or -1 if it is not present.
Parameters
- searchElement: T
  The value to locate in the array.
- fromIndex: number = 0
  The stream index at which to begin the search. If fromIndex is omitted, the search starts at index 0.
Returns number
Implementation of Stream.indexOf
- Defined in packages/langium/src/utils/stream.ts:371

isEmpty

isEmpty(): boolean
Determines whether this stream contains no elements.

Returns boolean
Implementation of Stream.isEmpty
- Defined in packages/langium/src/utils/stream.ts:283

iterator

iterator(): IterableIterator<T>
Returns an iterator for this stream. This is the same as calling the Symbol.iterator function property.

Returns IterableIterator<T>
Implementation of Stream.iterator
- Defined in packages/langium/src/utils/stream.ts:270

join

join(separator?): string
Adds all elements of the stream into a string, separated by the specified separator string.
Parameters
- separator: string = ','
  A string used to separate one element of the stream from the next in the resulting string. If omitted, the steam elements are separated with a comma.
Returns string
Implementation of Stream.join
- Defined in packages/langium/src/utils/stream.ts:353

limit

limit(maxSize): Stream<T>
Returns a stream consisting of the elements of this stream, truncated to be no longer than maxSize in length.
Parameters
- maxSize: number
 The number of elements the stream should be limited to
Returns Stream<T>
Implementation of Stream.limit
- Defined in packages/langium/src/utils/stream.ts:634

map

map(callbackfn): Stream
Returns a stream that yields the results of calling the specified callback function on each element of the stream. The function is called when the resulting stream elements are actually accessed, so accessing the resulting stream multiple times means the function is also called multiple times for each element of the stream.
Type Parameters
- U
Parameters
- callbackfn: ((value: T) => U)
 Lazily evaluated function mapping stream elements.
 - - (value): U
 - Parameters
 value: T
 Returns U
Returns Stream
Implementation of Stream.map
- Defined in packages/langium/src/utils/stream.ts:433

nonNullable

nonNullable(): Stream<NonNullable<T>>
Returns the elements of the stream that are non-nullable, which means they are neither undefined nor null.

Returns Stream<NonNullable<T>>
Implementation of Stream.nonNullable
- Defined in packages/langium/src/utils/stream.ts:466

`Protected`recursiveReduce

recursiveReduce(iterator, callbackfn, initialValue?): undefined | T | U
Type Parameters
- U
Parameters
- iterator: Iterator<T, any, undefined>
- callbackfn: ((previousValue: T | U, currentValue: T) => U)
 - - (previousValue, currentValue): U
 - Parameters
 previousValue: T | U
 currentValue: T
 Returns U
- OptionalinitialValue: U
Returns undefined | T | U
- Defined in packages/langium/src/utils/stream.ts:493

reduce

reduce(callbackfn): undefined | T
Calls the specified callback function for all elements in the stream. The return value of the callback function is the accumulated result, and is provided as an argument in the next call to the callback function.
Parameters
- callbackfn: ((previousValue: T, currentValue: T) => T)
  This method calls the function once for each element in the stream, providing the previous and current values of the reduction.
  - - (previousValue, currentValue): T
    - Parameters
      previousValue: T
      currentValue: T
      Returns T
Returns undefined | T
Implementation of Stream.reduce
- Defined in packages/langium/src/utils/stream.ts:470
reduce(callbackfn, initialValue): U
Calls the specified callback function for all elements in the stream. The return value of the callback function is the accumulated result, and is provided as an argument in the next call to the callback function.
Type Parameters
- U = T
Parameters
- callbackfn: ((previousValue: U, currentValue: T) => U)
  This method calls the function once for each element in the stream, providing the previous and current values of the reduction.
  - - (previousValue, currentValue): U
    - Parameters
      previousValue: U
      currentValue: T
      Returns U
- initialValue: U
  If specified, initialValue is used as the initial value to start the accumulation. The first call to the function provides this value as an argument instead of a stream value.
Returns U
Implementation of Stream.reduce
- Defined in packages/langium/src/utils/stream.ts:471

reduceRight

reduceRight(callbackfn): undefined | T
Calls the specified callback function for all elements in the stream, in descending order. The return value of the callback function is the accumulated result, and is provided as an argument in the next call to the callback function.
Parameters
- callbackfn: ((previousValue: T, currentValue: T) => T)
  This method calls the function once for each element in the stream, providing the previous and current values of the reduction.
  - - (previousValue, currentValue): T
    - Parameters
      previousValue: T
      currentValue: T
      Returns T
Returns undefined | T
Implementation of Stream.reduceRight
- Defined in packages/langium/src/utils/stream.ts:487
reduceRight(callbackfn, initialValue): U
Calls the specified callback function for all elements in the stream, in descending order. The return value of the callback function is the accumulated result, and is provided as an argument in the next call to the callback function.
Type Parameters
- U = T
Parameters
- callbackfn: ((previousValue: U, currentValue: T) => U)
  This method calls the function once for each element in the stream, providing the previous and current values of the reduction.
  - - (previousValue, currentValue): U
    - Parameters
      previousValue: U
      currentValue: T
      Returns U
- initialValue: U
  If specified, initialValue is used as the initial value to start the accumulation. The first call to the function provides this value as an argument instead of an array value.
Returns U
Implementation of Stream.reduceRight
- Defined in packages/langium/src/utils/stream.ts:488

some

some(predicate): boolean
Determines whether any member of the stream satisfies the specified test.
Parameters
- predicate: ((value: T) => unknown)
  This method calls the predicate function for each element in the stream until the predicate returns a value which is coercible to the Boolean value true, or until the end of the stream.
  - - (value): unknown
    - Parameters
      value: T
      Returns unknown
Returns boolean
Implementation of Stream.some
- Defined in packages/langium/src/utils/stream.ts:410

tail

tail(skipCount?): Stream<T>
Returns a stream that skips the first skipCount elements from this stream.
Parameters
- skipCount: number = 1
 The number of elements to skip. If this is larger than the number of elements in the stream, an empty stream is returned. Defaults to 1.
Returns Stream<T>
Implementation of Stream.tail
- Defined in packages/langium/src/utils/stream.ts:618

toArray

toArray(): T[]
Collects all elements of this stream into an array.

Returns T[]
Implementation of Stream.toArray
- Defined in packages/langium/src/utils/stream.ts:299

toMap

toMap<K, V>(keyFn?, valueFn?): Map<K, V>
Collects all elements of this stream into a Map, applying the provided functions to determine keys and values.
Type Parameters
- K = T
- V = T
Parameters
- OptionalkeyFn: ((e: T) => K)
 The function to derive map keys. If omitted, the stream elements are used as keys.
 - - (e): K
 - Parameters
 e: T
 Returns K
- OptionalvalueFn: ((e: T) => V)
 The function to derive map values. If omitted, the stream elements are used as values.
 - - (e): V
 - Parameters
 e: T
 Returns V
Returns Map<K, V>
Implementation of Stream.toMap
- Defined in packages/langium/src/utils/stream.ts:316

toSet

toSet(): Set<T>
Collects all elements of this stream into a Set.

Returns Set<T>
Implementation of Stream.toSet
- Defined in packages/langium/src/utils/stream.ts:312

toString

toString(): string
Returns a string representation of a stream.

Returns string
Implementation of Stream.toString
- Defined in packages/langium/src/utils/stream.ts:324

Class StreamImpl<S, T>

Type Parameters

Hierarchy (view full)

Implements

Index

Constructors

Properties

Methods

Constructors

constructor

Type Parameters

Parameters

Returns S

Parameters

Returns IteratorResult<T, undefined>

Returns StreamImpl<S, T>

Properties

Protected ReadonlynextFn

Protected ReadonlystartFn

Methods

[iterator]

Returns Iterator<T, any, undefined>

concat

Type Parameters

Parameters

Returns Stream<T | T2>

count

Returns number

distinct

Type Parameters

Parameters

Parameters

Returns Key

Returns Stream<T>

every

Type Parameters

Parameters

Parameters

Returns value is U

Returns this is Stream<U> & StreamImpl<S, T>

Parameters

Parameters

Returns unknown

Returns boolean

exclude

Type Parameters

Parameters

Parameters

Returns Key

Returns Stream<T>

filter

Type Parameters

Parameters

Parameters

Returns value is U

Returns Stream<U> & StreamImpl<S, T>

Parameters

Parameters

Returns unknown

Returns Stream<T> & StreamImpl<S, T>

find

Type Parameters

Parameters

Parameters

Returns value is S

Returns undefined | S

Parameters

Parameters

Returns unknown

Returns undefined | T

findIndex

Parameters

Parameters

Returns unknown

Returns number

flat

Type Parameters

Parameters

Returns FlatStream<T, D>

flatMap

`Protected` `Readonly`nextFn

`Protected` `Readonly`startFn

`Protected`recursiveReduce