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Aculix Technologies
6b01e4c246
Removes docs/superpowers, which held a design note and an implementation plan. Those were working notes rather than anything the project needs, and they don't belong in the repo. Everything else here is wording: em dashes swapped for ordinary punctuation across the README and the code comments, and a few sentences straightened out.
52 lines
1.4 KiB
JavaScript
52 lines
1.4 KiB
JavaScript
/** Bounded stack of reversible operations. Kept separate from tasks.js so that
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* module stays purely functional while this one holds the state. */
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export function createUndoStack(limit = 10) {
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const entries = []
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return {
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push(entry) {
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entries.push(entry)
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if (entries.length > limit) entries.shift()
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},
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pop() {
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return entries.length > 0 ? entries.pop() : null
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},
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get size() {
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return entries.length
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},
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clear() {
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entries.length = 0
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},
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}
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}
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/**
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* Reverses one entry against the current task list.
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*
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* Indices are clamped because the list may have changed since the entry was
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* recorded. A task deleted from position 5 can be restored into a list that
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* has since shrunk to two items, and landing at the end beats throwing.
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*
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* `clearCompleted` entries must record `removed` in ascending index order, so
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* re-inserting front to back puts each task back where it was.
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*/
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export function applyUndo(tasks, entry) {
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if (!entry) return tasks
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if (entry.type === 'delete') {
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const next = [...tasks]
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next.splice(Math.min(entry.index, next.length), 0, entry.task)
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return next
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}
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if (entry.type === 'clearCompleted') {
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const next = [...tasks]
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for (const { task, index } of entry.removed) {
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next.splice(Math.min(index, next.length), 0, task)
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}
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return next
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}
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return tasks
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}
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