57 lines
No EOL
1.4 KiB
JavaScript
57 lines
No EOL
1.4 KiB
JavaScript
import _extends from "@babel/runtime/helpers/esm/extends";
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/* eslint-disable no-cond-assign */
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export class Store {
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// HACK: `any` fixes adding listeners that accept partial state.
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// Internal state to handle recursive `setState()` calls
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static create(state) {
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return new Store(state);
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}
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constructor(state) {
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this.state = state;
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this.listeners = new Set();
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this.updateTick = 0;
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}
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subscribe = fn => {
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this.listeners.add(fn);
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return () => {
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this.listeners.delete(fn);
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};
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};
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getSnapshot = () => {
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return this.state;
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};
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setState(newState) {
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this.state = newState;
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this.updateTick += 1;
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const currentTick = this.updateTick;
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const it = this.listeners.values();
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let result;
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while (result = it.next(), !result.done) {
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if (currentTick !== this.updateTick) {
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// If the tick has changed, a recursive `setState` call has been made,
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// and it has already notified all listeners.
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return;
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}
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const listener = result.value;
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listener(newState);
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}
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}
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update(changes) {
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for (const key in changes) {
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if (!Object.is(this.state[key], changes[key])) {
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this.setState(_extends({}, this.state, changes));
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return;
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}
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}
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}
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set(key, value) {
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if (!Object.is(this.state[key], value)) {
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this.setState(_extends({}, this.state, {
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[key]: value
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}));
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}
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}
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} |