| 1 | import {Transform} from 'vega-dataflow';
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| 2 | import {inherits} from 'vega-util';
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| 3 |
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| 4 | /**
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| 5 | * Propagates a new pulse without any tuples so long as the input
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| 6 | * pulse contains some added, removed or modified tuples.
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| 7 | * @param {object} params - The parameters for this operator.
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| 8 | * @constructor
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| 9 | */
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| 10 | export default function Sieve(params) {
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| 11 | Transform.call(this, null, params);
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| 12 | this.modified(true); // always treat as modified
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| 13 | }
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| 14 |
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| 15 | inherits(Sieve, Transform, {
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| 16 | transform(_, pulse) {
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| 17 | this.value = pulse.source;
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| 18 | return pulse.changed()
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| 19 | ? pulse.fork(pulse.NO_SOURCE | pulse.NO_FIELDS)
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| 20 | : pulse.StopPropagation;
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| 21 | }
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| 22 | });
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| 23 |
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