2022-01-21 08:28:41 +00:00
|
|
|
import { Observable } from '../Observable';
|
|
|
|
import { SchedulerLike } from '../types';
|
2022-05-29 09:24:36 +00:00
|
|
|
export declare type ConditionFunc<S> = (state: S) => boolean;
|
|
|
|
export declare type IterateFunc<S> = (state: S) => S;
|
|
|
|
export declare type ResultFunc<S, T> = (state: S) => T;
|
2022-01-21 08:28:41 +00:00
|
|
|
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.
|
|
|
|
*
|
|
|
|
* ![](generate.png)
|
|
|
|
*
|
2022-05-29 09:24:36 +00:00
|
|
|
* @example <caption>Produces sequence of 0, 1, 2, ... 9, then completes.</caption>
|
|
|
|
* const res = generate(0, x => x < 10, x => x + 1, x => x);
|
2022-01-21 08:28:41 +00:00
|
|
|
*
|
2022-05-29 09:24:36 +00:00
|
|
|
* @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);
|
2022-01-21 08:28:41 +00:00
|
|
|
*
|
|
|
|
* @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 declare 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>
|
|
|
|
*
|
2022-05-29 09:24:36 +00:00
|
|
|
* <img src="./img/generate.png" width="100%">
|
2022-01-21 08:28:41 +00:00
|
|
|
*
|
2022-05-29 09:24:36 +00:00
|
|
|
* `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
|
2022-01-21 08:28:41 +00:00
|
|
|
* is a function that accepts this value and tests if some condition still holds. If it does,
|
2022-05-29 09:24:36 +00:00
|
|
|
* 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).
|
2022-01-21 08:28:41 +00:00
|
|
|
*
|
|
|
|
* Return value of a `generate` operator is an Observable that on each loop iteration
|
2022-05-29 09:24:36 +00:00
|
|
|
* 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
|
2022-01-21 08:28:41 +00:00
|
|
|
* completes at that moment.
|
|
|
|
*
|
2022-05-29 09:24:36 +00:00
|
|
|
* 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.
|
2022-01-21 08:28:41 +00:00
|
|
|
*
|
|
|
|
* If you find three anonymous functions in `generate` call hard to read, you can provide
|
2022-05-29 09:24:36 +00:00
|
|
|
* single object to the operator instead. That object has properties: `initialState`,
|
2022-01-21 08:28:41 +00:00
|
|
|
* `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
|
2022-05-29 09:24:36 +00:00
|
|
|
* 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
|
2022-01-21 08:28:41 +00:00
|
|
|
* by default (when no scheduler is passed) values are simply emitted synchronously.
|
|
|
|
*
|
|
|
|
*
|
2022-05-29 09:24:36 +00:00
|
|
|
* @example <caption>Use with condition and iterate functions.</caption>
|
|
|
|
* const generated = generate(0, x => x < 3, x => x + 1);
|
2022-01-21 08:28:41 +00:00
|
|
|
*
|
2022-05-29 09:24:36 +00:00
|
|
|
* generated.subscribe(
|
|
|
|
* value => console.log(value),
|
|
|
|
* err => {},
|
|
|
|
* () => console.log('Yo!')
|
|
|
|
* );
|
2022-01-21 08:28:41 +00:00
|
|
|
*
|
|
|
|
* // Logs:
|
|
|
|
* // 0
|
|
|
|
* // 1
|
|
|
|
* // 2
|
2022-05-29 09:24:36 +00:00
|
|
|
* // "Yo!"
|
2022-01-21 08:28:41 +00:00
|
|
|
*
|
|
|
|
*
|
2022-05-29 09:24:36 +00:00
|
|
|
* @example <caption>Use with condition, iterate and resultSelector functions.</caption>
|
|
|
|
* const generated = generate(0, x => x < 3, x => x + 1, x => x * 1000);
|
2022-01-21 08:28:41 +00:00
|
|
|
*
|
2022-05-29 09:24:36 +00:00
|
|
|
* generated.subscribe(
|
|
|
|
* value => console.log(value),
|
|
|
|
* err => {},
|
|
|
|
* () => console.log('Yo!')
|
|
|
|
* );
|
2022-01-21 08:28:41 +00:00
|
|
|
*
|
|
|
|
* // Logs:
|
|
|
|
* // 0
|
|
|
|
* // 1000
|
|
|
|
* // 2000
|
2022-05-29 09:24:36 +00:00
|
|
|
* // "Yo!"
|
2022-01-21 08:28:41 +00:00
|
|
|
*
|
|
|
|
*
|
2022-05-29 09:24:36 +00:00
|
|
|
* @example <caption>Use with options object.</caption>
|
|
|
|
* const generated = generate({
|
2022-01-21 08:28:41 +00:00
|
|
|
* initialState: 0,
|
|
|
|
* condition(value) { return value < 3; },
|
|
|
|
* iterate(value) { return value + 1; },
|
|
|
|
* resultSelector(value) { return value * 1000; }
|
|
|
|
* });
|
|
|
|
*
|
2022-05-29 09:24:36 +00:00
|
|
|
* generated.subscribe(
|
|
|
|
* value => console.log(value),
|
|
|
|
* err => {},
|
|
|
|
* () => console.log('Yo!')
|
|
|
|
* );
|
2022-01-21 08:28:41 +00:00
|
|
|
*
|
|
|
|
* // Logs:
|
|
|
|
* // 0
|
|
|
|
* // 1000
|
|
|
|
* // 2000
|
2022-05-29 09:24:36 +00:00
|
|
|
* // "Yo!"
|
2022-01-21 08:28:41 +00:00
|
|
|
*
|
2022-05-29 09:24:36 +00:00
|
|
|
* @example <caption>Use options object without condition function.</caption>
|
|
|
|
* const generated = generate({
|
2022-01-21 08:28:41 +00:00
|
|
|
* initialState: 0,
|
|
|
|
* iterate(value) { return value + 1; },
|
|
|
|
* resultSelector(value) { return value * 1000; }
|
|
|
|
* });
|
|
|
|
*
|
2022-05-29 09:24:36 +00:00
|
|
|
* generated.subscribe(
|
|
|
|
* value => console.log(value),
|
|
|
|
* err => {},
|
|
|
|
* () => console.log('Yo!') // This will never run.
|
|
|
|
* );
|
2022-01-21 08:28:41 +00:00
|
|
|
*
|
|
|
|
* // Logs:
|
|
|
|
* // 0
|
|
|
|
* // 1000
|
|
|
|
* // 2000
|
|
|
|
* // 3000
|
|
|
|
* // ...and never stops.
|
2022-05-29 09:24:36 +00:00
|
|
|
*
|
2022-01-21 08:28:41 +00:00
|
|
|
*
|
|
|
|
* @see {@link from}
|
2022-05-29 09:24:36 +00:00
|
|
|
* @see {@link index/Observable.create}
|
2022-01-21 08:28:41 +00:00
|
|
|
*
|
|
|
|
* @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 declare 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.
|
|
|
|
*
|
|
|
|
* ![](generate.png)
|
|
|
|
*
|
2022-05-29 09:24:36 +00:00
|
|
|
* @example <caption>Produces sequence of 0, 1, 2, ... 9, then completes.</caption>
|
|
|
|
* const res = generate({
|
2022-01-21 08:28:41 +00:00
|
|
|
* initialState: 0,
|
2022-05-29 09:24:36 +00:00
|
|
|
* condition: x => x < 10,
|
|
|
|
* iterate: x => x + 1,
|
2022-01-21 08:28:41 +00:00
|
|
|
* });
|
|
|
|
*
|
|
|
|
* @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 declare 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.
|
|
|
|
*
|
|
|
|
* ![](generate.png)
|
|
|
|
*
|
2022-05-29 09:24:36 +00:00
|
|
|
* @example <caption>Produces sequence of 0, 1, 2, ... 9, then completes.</caption>
|
|
|
|
* const res = generate({
|
2022-01-21 08:28:41 +00:00
|
|
|
* initialState: 0,
|
2022-05-29 09:24:36 +00:00
|
|
|
* condition: x => x < 10,
|
2022-01-21 08:28:41 +00:00
|
|
|
* iterate: x => x + 1,
|
2022-05-29 09:24:36 +00:00
|
|
|
* resultSelector: x => x,
|
2022-01-21 08:28:41 +00:00
|
|
|
* });
|
|
|
|
*
|
|
|
|
* @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 declare function generate<T, S>(options: GenerateOptions<T, S>): Observable<T>;
|