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49 lines
1.6 KiB
49 lines
1.6 KiB
/**
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* Module to help deal with unsaved changes when closing a page.
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*/
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import {Disposable} from 'grainjs';
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/**
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* Create an UnsavedChanges object to indicate there are UnsavedChanges. Dispose it when this is
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* no longer the case. The optional callback will be called to confirm there are indeed unsaved
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* changes. If omitted, it is assumed that there are.
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*/
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export class UnsavedChange extends Disposable {
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constructor(
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// If given, saveChanges() will call it to save changes.
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private _saveCB?: () => Promise<void>,
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// If given, it may return false to indicate that actually nothing has changed.
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private _haveChanges?: () => boolean,
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) {
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super();
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unsavedChanges.add(this);
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this.onDispose(() => unsavedChanges.delete(this));
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}
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public haveUnsavedChanges() { return !this._haveChanges || this._haveChanges(); }
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public async save(): Promise<void> { return this._saveCB && this._saveCB(); }
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}
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export class UnsavedChangeSet {
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private _changes = new Set<UnsavedChange>();
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/**
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* Check if there are any unsaved changes out there.
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*/
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public haveUnsavedChanges(): boolean {
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return Array.from(this._changes).some((c) => c.haveUnsavedChanges());
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}
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/**
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* Save any unsaved changes out there.
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*/
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public async saveChanges(): Promise<void> {
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await Promise.all(Array.from(this._changes).map((c) => c.save()));
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}
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public add(unsaved: UnsavedChange) { this._changes.add(unsaved); }
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public delete(unsaved: UnsavedChange) { this._changes.delete(unsaved); }
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}
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// Global set of UnsavedChanges, checked on page unload.
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export const unsavedChanges = new UnsavedChangeSet();
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