39 lines
1.4 KiB
JavaScript
39 lines
1.4 KiB
JavaScript
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import { reduce } from './reduce';
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/**
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* The Max operator operates on an Observable that emits numbers (or items that can be compared with a provided function),
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* and when source Observable completes it emits a single item: the item with the largest value.
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*
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* <img src="./img/max.png" width="100%">
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*
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* @example <caption>Get the maximal value of a series of numbers</caption>
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* Rx.Observable.of(5, 4, 7, 2, 8)
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* .max()
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* .subscribe(x => console.log(x)); // -> 8
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*
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* @example <caption>Use a comparer function to get the maximal item</caption>
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* interface Person {
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* age: number,
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* name: string
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* }
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* Observable.of<Person>({age: 7, name: 'Foo'},
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* {age: 5, name: 'Bar'},
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* {age: 9, name: 'Beer'})
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* .max<Person>((a: Person, b: Person) => a.age < b.age ? -1 : 1)
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* .subscribe((x: Person) => console.log(x.name)); // -> 'Beer'
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* }
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*
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* @see {@link min}
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*
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* @param {Function} [comparer] - Optional comparer function that it will use instead of its default to compare the
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* value of two items.
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* @return {Observable} An Observable that emits item with the largest value.
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* @method max
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* @owner Observable
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*/
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export function max(comparer) {
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const max = (typeof comparer === 'function')
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? (x, y) => comparer(x, y) > 0 ? x : y
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: (x, y) => x > y ? x : y;
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return reduce(max);
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}
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//# sourceMappingURL=max.js.map
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