18 lines
384 B
JavaScript
18 lines
384 B
JavaScript
/**
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* ES6 Map with additional `add` method to accumulate items.
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*/
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export class AccumulatorMap extends Map {
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get [Symbol.toStringTag]() {
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return 'AccumulatorMap';
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}
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add(key, item) {
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const group = this.get(key);
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if (group === undefined) {
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this.set(key, [item]);
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}
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else {
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group.push(item);
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}
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}
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}
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