1 | ;
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2 | Object.defineProperty(exports, "__esModule", { value: true });
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3 | /*-----------------------------------------------------------------------------
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4 | | Copyright (c) 2014-2017, PhosphorJS Contributors
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5 | |
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6 | | Distributed under the terms of the BSD 3-Clause License.
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7 | |
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8 | | The full license is in the file LICENSE, distributed with this software.
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9 | |----------------------------------------------------------------------------*/
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10 | var iter_1 = require("./iter");
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11 | /**
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12 | * Filter an iterable for values which pass a test.
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13 | *
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14 | * @param object - The iterable or array-like object of interest.
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15 | *
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16 | * @param fn - The predicate function to invoke for each value.
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17 | *
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18 | * @returns An iterator which yields the values which pass the test.
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19 | *
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20 | * #### Example
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21 | * ```typescript
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22 | * import { filter, toArray } from '@phosphor/algorithm';
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23 | *
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24 | * let data = [1, 2, 3, 4, 5, 6];
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25 | *
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26 | * let stream = filter(data, value => value % 2 === 0);
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27 | *
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28 | * toArray(stream); // [2, 4, 6]
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29 | * ```
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30 | */
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31 | function filter(object, fn) {
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32 | return new FilterIterator(iter_1.iter(object), fn);
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33 | }
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34 | exports.filter = filter;
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35 | /**
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36 | * An iterator which yields values which pass a test.
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37 | */
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38 | var FilterIterator = /** @class */ (function () {
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39 | /**
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40 | * Construct a new filter iterator.
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41 | *
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42 | * @param source - The iterator of values of interest.
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43 | *
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44 | * @param fn - The predicate function to invoke for each value.
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45 | */
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46 | function FilterIterator(source, fn) {
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47 | this._index = 0;
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48 | this._source = source;
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49 | this._fn = fn;
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50 | }
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51 | /**
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52 | * Get an iterator over the object's values.
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53 | *
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54 | * @returns An iterator which yields the object's values.
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55 | */
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56 | FilterIterator.prototype.iter = function () {
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57 | return this;
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58 | };
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59 | /**
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60 | * Create an independent clone of the iterator.
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61 | *
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62 | * @returns A new independent clone of the iterator.
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63 | */
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64 | FilterIterator.prototype.clone = function () {
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65 | var result = new FilterIterator(this._source.clone(), this._fn);
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66 | result._index = this._index;
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67 | return result;
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68 | };
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69 | /**
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70 | * Get the next value from the iterator.
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71 | *
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72 | * @returns The next value from the iterator, or `undefined`.
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73 | */
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74 | FilterIterator.prototype.next = function () {
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75 | var fn = this._fn;
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76 | var it = this._source;
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77 | var value;
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78 | while ((value = it.next()) !== undefined) {
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79 | if (fn(value, this._index++)) {
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80 | return value;
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81 | }
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82 | }
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83 | return undefined;
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84 | };
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85 | return FilterIterator;
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86 | }());
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87 | exports.FilterIterator = FilterIterator;
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