forked from mystiq/hydrogen-web
223 lines
6.6 KiB
JavaScript
223 lines
6.6 KiB
JavaScript
/*
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Copyright 2020 Bruno Windels <bruno@windels.cloud>
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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import {BaseObservableMap} from "./BaseObservableMap";
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export class FilteredMap extends BaseObservableMap {
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constructor(source, filter) {
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super();
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this._source = source;
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this._filter = filter;
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/** @type {Map<string, bool>} */
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this._included = null;
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this._subscription = null;
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}
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setFilter(filter) {
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this._filter = filter;
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if (this._subscription) {
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this._reapplyFilter();
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}
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}
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/**
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* reapply the filter
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*/
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_reapplyFilter(silent = false) {
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if (this._filter) {
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const oldIncluded = this._included;
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this._included = this._included || new Map();
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for (const [key, value] of this._source) {
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const isIncluded = this._filter(value, key);
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this._included.set(key, isIncluded);
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if (!silent) {
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const wasIncluded = oldIncluded ? oldIncluded.get(key) : true;
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this._emitForUpdate(wasIncluded, isIncluded, key, value);
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}
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}
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} else { // no filter
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// did we have a filter before?
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if (this._included && !silent) {
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// add any non-included items again
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for (const [key, value] of this._source) {
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if (!this._included.get(key)) {
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this.emitAdd(key, value);
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}
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}
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}
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this._included = null;
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}
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}
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onAdd(key, value) {
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if (this._filter) {
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const included = this._filter(value, key);
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this._included.set(key, included);
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if (!included) {
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return;
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}
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}
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this.emitAdd(key, value);
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}
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onRemove(key, value) {
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const wasIncluded = !this._filter || this._included.get(key);
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this._included.delete(key);
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if (wasIncluded) {
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this.emitRemove(key, value);
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}
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}
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onUpdate(key, value, params) {
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// if an update is emitted while calling source.subscribe() from onSubscribeFirst, ignore it
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if (!this._included) {
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return;
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}
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if (this._filter) {
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const wasIncluded = this._included.get(key);
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const isIncluded = this._filter(value, key);
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this._included.set(key, isIncluded);
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this._emitForUpdate(wasIncluded, isIncluded, key, value, params);
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} else {
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this.emitUpdate(key, value, params);
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}
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}
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_emitForUpdate(wasIncluded, isIncluded, key, value, params = null) {
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if (wasIncluded && !isIncluded) {
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this.emitRemove(key, value);
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} else if (!wasIncluded && isIncluded) {
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this.emitAdd(key, value);
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} else if (wasIncluded && isIncluded) {
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this.emitUpdate(key, value, params);
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}
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}
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onSubscribeFirst() {
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this._subscription = this._source.subscribe(this);
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this._reapplyFilter(true);
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super.onSubscribeFirst();
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}
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onUnsubscribeLast() {
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super.onUnsubscribeLast();
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this._included = null;
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this._subscription = this._subscription();
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}
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onReset() {
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this._reapplyFilter();
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this.emitReset();
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}
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[Symbol.iterator]() {
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return new FilterIterator(this._source, this._included);
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}
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get size() {
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let count = 0;
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this._included.forEach(included => {
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if (included) {
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count += 1;
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}
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});
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return count;
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}
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get(key) {
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const value = this._source.get(key);
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if (value && this._filter(value, key)) {
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return value;
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}
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}
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}
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class FilterIterator {
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constructor(map, _included) {
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this._included = _included;
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this._sourceIterator = map[Symbol.iterator]();
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}
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next() {
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// eslint-disable-next-line no-constant-condition
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while (true) {
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const sourceResult = this._sourceIterator.next();
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if (sourceResult.done) {
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return sourceResult;
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}
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const key = sourceResult.value[0];
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if (this._included.get(key)) {
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return sourceResult;
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}
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}
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}
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}
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import {ObservableMap} from "./ObservableMap";
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export function tests() {
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return {
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"filter preloaded list": assert => {
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const source = new ObservableMap();
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source.add("one", 1);
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source.add("two", 2);
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source.add("three", 3);
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const oddNumbers = new FilteredMap(source, x => x % 2 !== 0);
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// can only iterate after subscribing
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oddNumbers.subscribe({});
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assert.equal(oddNumbers.size, 2);
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const it = oddNumbers[Symbol.iterator]();
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assert.deepEqual(it.next().value, ["one", 1]);
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assert.deepEqual(it.next().value, ["three", 3]);
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assert.equal(it.next().done, true);
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},
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// "filter added values": assert => {
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// },
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// "filter removed values": assert => {
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// },
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// "filter changed values": assert => {
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// },
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"emits must trigger once": assert => {
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const source = new ObservableMap();
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let count_add = 0, count_update = 0, count_remove = 0;
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source.add("num1", 1);
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source.add("num2", 2);
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source.add("num3", 3);
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const oddMap = new FilteredMap(source, x => x % 2 !== 0);
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oddMap.subscribe({
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onAdd() {
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count_add += 1;
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},
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onRemove() {
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count_remove += 1;
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},
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onUpdate() {
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count_update += 1;
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}
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});
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source.set("num3", 4);
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source.set("num3", 5);
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source.set("num3", 7);
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assert.strictEqual(count_add, 1);
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assert.strictEqual(count_update, 1);
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assert.strictEqual(count_remove, 1);
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}
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}
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}
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