+++ /dev/null
-import { Observable } from '../Observable';
-import { Subscriber } from '../Subscriber';
-import { identity } from '../util/identity';
-import { SchedulerAction, SchedulerLike } from '../types';
-import { isScheduler } from '../util/isScheduler';
-
-export type ConditionFunc<S> = (state: S) => boolean;
-export type IterateFunc<S> = (state: S) => S;
-export type ResultFunc<S, T> = (state: S) => T;
-
-interface SchedulerState<T, S> {
- needIterate?: boolean;
- state: S;
- subscriber: Subscriber<T>;
- condition?: ConditionFunc<S>;
- iterate: IterateFunc<S>;
- resultSelector: ResultFunc<S, T>;
-}
-
-export interface GenerateBaseOptions<S> {
- /**
- * Initial state.
- */
- initialState: S;
- /**
- * Condition function that accepts state and returns boolean.
- * When it returns false, the generator stops.
- * If not specified, a generator never stops.
- */
- condition?: ConditionFunc<S>;
- /**
- * Iterate function that accepts state and returns new state.
- */
- iterate: IterateFunc<S>;
- /**
- * SchedulerLike to use for generation process.
- * By default, a generator starts immediately.
- */
- scheduler?: SchedulerLike;
-}
-
-export interface GenerateOptions<T, S> extends GenerateBaseOptions<S> {
- /**
- * Result selection function that accepts state and returns a value to emit.
- */
- resultSelector: ResultFunc<S, T>;
-}
-
-/**
- * Generates an observable sequence by running a state-driven loop
- * producing the sequence's elements, using the specified scheduler
- * to send out observer messages.
- *
- * 
- *
- * @example <caption>Produces sequence of 0, 1, 2, ... 9, then completes.</caption>
- * const res = generate(0, x => x < 10, x => x + 1, x => x);
- *
- * @example <caption>Using asap scheduler, produces sequence of 2, 3, 5, then completes.</caption>
- * const res = generate(1, x => x < 5, x => x * 2, x => x + 1, asap);
- *
- * @see {@link from}
- * @see {@link Observable}
- *
- * @param {S} initialState Initial state.
- * @param {function (state: S): boolean} condition Condition to terminate generation (upon returning false).
- * @param {function (state: S): S} iterate Iteration step function.
- * @param {function (state: S): T} resultSelector Selector function for results produced in the sequence. (deprecated)
- * @param {SchedulerLike} [scheduler] A {@link SchedulerLike} on which to run the generator loop. If not provided, defaults to emit immediately.
- * @returns {Observable<T>} The generated sequence.
- */
- export function generate<T, S>(initialState: S,
- condition: ConditionFunc<S>,
- iterate: IterateFunc<S>,
- resultSelector: ResultFunc<S, T>,
- scheduler?: SchedulerLike): Observable<T>;
-
-/**
- * Generates an Observable by running a state-driven loop
- * that emits an element on each iteration.
- *
- * <span class="informal">Use it instead of nexting values in a for loop.</span>
- *
- * <img src="./img/generate.png" width="100%">
- *
- * `generate` allows you to create stream of values generated with a loop very similar to
- * traditional for loop. First argument of `generate` is a beginning value. Second argument
- * is a function that accepts this value and tests if some condition still holds. If it does,
- * loop continues, if not, it stops. Third value is a function which takes previously defined
- * value and modifies it in some way on each iteration. Note how these three parameters
- * are direct equivalents of three expressions in regular for loop: first expression
- * initializes some state (for example numeric index), second tests if loop can make next
- * iteration (for example if index is lower than 10) and third states how defined value
- * will be modified on every step (index will be incremented by one).
- *
- * Return value of a `generate` operator is an Observable that on each loop iteration
- * emits a value. First, condition function is ran. If it returned true, Observable
- * emits currently stored value (initial value at the first iteration) and then updates
- * that value with iterate function. If at some point condition returned false, Observable
- * completes at that moment.
- *
- * Optionally you can pass fourth parameter to `generate` - a result selector function which allows you
- * to immediately map value that would normally be emitted by an Observable.
- *
- * If you find three anonymous functions in `generate` call hard to read, you can provide
- * single object to the operator instead. That object has properties: `initialState`,
- * `condition`, `iterate` and `resultSelector`, which should have respective values that you
- * would normally pass to `generate`. `resultSelector` is still optional, but that form
- * of calling `generate` allows you to omit `condition` as well. If you omit it, that means
- * condition always holds, so output Observable will never complete.
- *
- * Both forms of `generate` can optionally accept a scheduler. In case of multi-parameter call,
- * scheduler simply comes as a last argument (no matter if there is resultSelector
- * function or not). In case of single-parameter call, you can provide it as a
- * `scheduler` property on object passed to the operator. In both cases scheduler decides when
- * next iteration of the loop will happen and therefore when next value will be emitted
- * by the Observable. For example to ensure that each value is pushed to the observer
- * on separate task in event loop, you could use `async` scheduler. Note that
- * by default (when no scheduler is passed) values are simply emitted synchronously.
- *
- *
- * @example <caption>Use with condition and iterate functions.</caption>
- * const generated = generate(0, x => x < 3, x => x + 1);
- *
- * generated.subscribe(
- * value => console.log(value),
- * err => {},
- * () => console.log('Yo!')
- * );
- *
- * // Logs:
- * // 0
- * // 1
- * // 2
- * // "Yo!"
- *
- *
- * @example <caption>Use with condition, iterate and resultSelector functions.</caption>
- * const generated = generate(0, x => x < 3, x => x + 1, x => x * 1000);
- *
- * generated.subscribe(
- * value => console.log(value),
- * err => {},
- * () => console.log('Yo!')
- * );
- *
- * // Logs:
- * // 0
- * // 1000
- * // 2000
- * // "Yo!"
- *
- *
- * @example <caption>Use with options object.</caption>
- * const generated = generate({
- * initialState: 0,
- * condition(value) { return value < 3; },
- * iterate(value) { return value + 1; },
- * resultSelector(value) { return value * 1000; }
- * });
- *
- * generated.subscribe(
- * value => console.log(value),
- * err => {},
- * () => console.log('Yo!')
- * );
- *
- * // Logs:
- * // 0
- * // 1000
- * // 2000
- * // "Yo!"
- *
- * @example <caption>Use options object without condition function.</caption>
- * const generated = generate({
- * initialState: 0,
- * iterate(value) { return value + 1; },
- * resultSelector(value) { return value * 1000; }
- * });
- *
- * generated.subscribe(
- * value => console.log(value),
- * err => {},
- * () => console.log('Yo!') // This will never run.
- * );
- *
- * // Logs:
- * // 0
- * // 1000
- * // 2000
- * // 3000
- * // ...and never stops.
- *
- *
- * @see {@link from}
- * @see {@link index/Observable.create}
- *
- * @param {S} initialState Initial state.
- * @param {function (state: S): boolean} condition Condition to terminate generation (upon returning false).
- * @param {function (state: S): S} iterate Iteration step function.
- * @param {function (state: S): T} [resultSelector] Selector function for results produced in the sequence.
- * @param {Scheduler} [scheduler] A {@link Scheduler} on which to run the generator loop. If not provided, defaults to emitting immediately.
- * @return {Observable<T>} The generated sequence.
- */
-export function generate<S>(initialState: S,
- condition: ConditionFunc<S>,
- iterate: IterateFunc<S>,
- scheduler?: SchedulerLike): Observable<S>;
-
-/**
- * Generates an observable sequence by running a state-driven loop
- * producing the sequence's elements, using the specified scheduler
- * to send out observer messages.
- * The overload accepts options object that might contain initial state, iterate,
- * condition and scheduler.
- *
- * 
- *
- * @example <caption>Produces sequence of 0, 1, 2, ... 9, then completes.</caption>
- * const res = generate({
- * initialState: 0,
- * condition: x => x < 10,
- * iterate: x => x + 1,
- * });
- *
- * @see {@link from}
- * @see {@link Observable}
- *
- * @param {GenerateBaseOptions<S>} options Object that must contain initialState, iterate and might contain condition and scheduler.
- * @returns {Observable<S>} The generated sequence.
- */
-export function generate<S>(options: GenerateBaseOptions<S>): Observable<S>;
-
-/**
- * Generates an observable sequence by running a state-driven loop
- * producing the sequence's elements, using the specified scheduler
- * to send out observer messages.
- * The overload accepts options object that might contain initial state, iterate,
- * condition, result selector and scheduler.
- *
- * 
- *
- * @example <caption>Produces sequence of 0, 1, 2, ... 9, then completes.</caption>
- * const res = generate({
- * initialState: 0,
- * condition: x => x < 10,
- * iterate: x => x + 1,
- * resultSelector: x => x,
- * });
- *
- * @see {@link from}
- * @see {@link Observable}
- *
- * @param {GenerateOptions<T, S>} options Object that must contain initialState, iterate, resultSelector and might contain condition and scheduler.
- * @returns {Observable<T>} The generated sequence.
- */
-export function generate<T, S>(options: GenerateOptions<T, S>): Observable<T>;
-
-export function generate<T, S>(initialStateOrOptions: S | GenerateOptions<T, S>,
- condition?: ConditionFunc<S>,
- iterate?: IterateFunc<S>,
- resultSelectorOrObservable?: (ResultFunc<S, T>) | SchedulerLike,
- scheduler?: SchedulerLike): Observable<T> {
-
- let resultSelector: ResultFunc<S, T>;
- let initialState: S;
-
- if (arguments.length == 1) {
- const options = initialStateOrOptions as GenerateOptions<T, S>;
- initialState = options.initialState;
- condition = options.condition;
- iterate = options.iterate;
- resultSelector = options.resultSelector || identity as ResultFunc<S, T>;
- scheduler = options.scheduler;
- } else if (resultSelectorOrObservable === undefined || isScheduler(resultSelectorOrObservable)) {
- initialState = initialStateOrOptions as S;
- resultSelector = identity as ResultFunc<S, T>;
- scheduler = resultSelectorOrObservable as SchedulerLike;
- } else {
- initialState = initialStateOrOptions as S;
- resultSelector = resultSelectorOrObservable as ResultFunc<S, T>;
- }
-
- return new Observable<T>(subscriber => {
- let state = initialState;
- if (scheduler) {
- return scheduler.schedule<SchedulerState<T, S>>(dispatch, 0, {
- subscriber,
- iterate,
- condition,
- resultSelector,
- state
- });
- }
-
- do {
- if (condition) {
- let conditionResult: boolean;
- try {
- conditionResult = condition(state);
- } catch (err) {
- subscriber.error(err);
- return undefined;
- }
- if (!conditionResult) {
- subscriber.complete();
- break;
- }
- }
- let value: T;
- try {
- value = resultSelector(state);
- } catch (err) {
- subscriber.error(err);
- return undefined;
- }
- subscriber.next(value);
- if (subscriber.closed) {
- break;
- }
- try {
- state = iterate(state);
- } catch (err) {
- subscriber.error(err);
- return undefined;
- }
- } while (true);
-
- return undefined;
- });
-}
-
-function dispatch<T, S>(this: SchedulerAction<SchedulerState<T, S>>, state: SchedulerState<T, S>) {
- const { subscriber, condition } = state;
- if (subscriber.closed) {
- return undefined;
- }
- if (state.needIterate) {
- try {
- state.state = state.iterate(state.state);
- } catch (err) {
- subscriber.error(err);
- return undefined;
- }
- } else {
- state.needIterate = true;
- }
- if (condition) {
- let conditionResult: boolean;
- try {
- conditionResult = condition(state.state);
- } catch (err) {
- subscriber.error(err);
- return undefined;
- }
- if (!conditionResult) {
- subscriber.complete();
- return undefined;
- }
- if (subscriber.closed) {
- return undefined;
- }
- }
- let value: T;
- try {
- value = state.resultSelector(state.state);
- } catch (err) {
- subscriber.error(err);
- return undefined;
- }
- if (subscriber.closed) {
- return undefined;
- }
- subscriber.next(value);
- if (subscriber.closed) {
- return undefined;
- }
- return this.schedule(state);
-}
projects / dotfiles / .git / blobdiff