1 | import { Subscriber } from '../Subscriber';
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2 | import { EmptyError } from '../util/EmptyError';
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3 | export function single(predicate) {
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4 | return (source) => source.lift(new SingleOperator(predicate, source));
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5 | }
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6 | class SingleOperator {
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7 | constructor(predicate, source) {
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8 | this.predicate = predicate;
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9 | this.source = source;
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10 | }
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11 | call(subscriber, source) {
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12 | return source.subscribe(new SingleSubscriber(subscriber, this.predicate, this.source));
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13 | }
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14 | }
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15 | class SingleSubscriber extends Subscriber {
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16 | constructor(destination, predicate, source) {
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17 | super(destination);
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18 | this.predicate = predicate;
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19 | this.source = source;
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20 | this.seenValue = false;
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21 | this.index = 0;
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22 | }
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23 | applySingleValue(value) {
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24 | if (this.seenValue) {
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25 | this.destination.error('Sequence contains more than one element');
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26 | }
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27 | else {
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28 | this.seenValue = true;
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29 | this.singleValue = value;
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30 | }
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31 | }
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32 | _next(value) {
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33 | const index = this.index++;
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34 | if (this.predicate) {
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35 | this.tryNext(value, index);
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36 | }
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37 | else {
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38 | this.applySingleValue(value);
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39 | }
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40 | }
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41 | tryNext(value, index) {
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42 | try {
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43 | if (this.predicate(value, index, this.source)) {
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44 | this.applySingleValue(value);
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45 | }
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46 | }
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47 | catch (err) {
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48 | this.destination.error(err);
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49 | }
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50 | }
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51 | _complete() {
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52 | const destination = this.destination;
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53 | if (this.index > 0) {
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54 | destination.next(this.seenValue ? this.singleValue : undefined);
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55 | destination.complete();
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56 | }
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57 | else {
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58 | destination.error(new EmptyError);
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59 | }
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60 | }
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61 | }
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62 | //# sourceMappingURL=single.js.map |
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