59 lines
1.6 KiB
TypeScript
59 lines
1.6 KiB
TypeScript
/**
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* ViewHistory — lightweight in-app navigation stack for rApps.
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*
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* Each rApp with hierarchical views instantiates one, calls push()
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* on forward navigation, and back() from the back button. Replaces
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* hardcoded data-back targets with a proper history stack.
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*/
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export interface ViewEntry<V extends string> {
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view: V;
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context?: Record<string, unknown>;
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}
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const MAX_DEPTH = 20;
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export class ViewHistory<V extends string> {
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private stack: ViewEntry<V>[] = [];
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private root: V;
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constructor(rootView: V) {
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this.root = rootView;
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}
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/** Record a forward navigation. Skips if top of stack is same view+context. */
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push(view: V, context?: Record<string, unknown>): void {
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const top = this.stack[this.stack.length - 1];
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if (top && top.view === view) return; // skip duplicate
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this.stack.push({ view, context });
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if (this.stack.length > MAX_DEPTH) this.stack.shift();
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}
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/** Pop and return the previous entry, or null if at root. */
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back(): ViewEntry<V> | null {
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if (this.stack.length <= 1) {
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this.stack = [];
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return { view: this.root };
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}
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this.stack.pop(); // remove current
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return this.stack[this.stack.length - 1] ?? { view: this.root };
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}
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/** True when there's history to go back to. */
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get canGoBack(): boolean {
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return this.stack.length > 1;
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}
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/** Peek at the previous entry without popping. */
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peekBack(): ViewEntry<V> | null {
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if (this.stack.length <= 1) return { view: this.root };
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return this.stack[this.stack.length - 2] ?? null;
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}
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/** Clear the stack and reset to a root view (e.g. on space switch). */
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reset(rootView?: V): void {
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if (rootView !== undefined) this.root = rootView;
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this.stack = [];
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}
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}
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