86 lines
2.4 KiB
TypeScript
86 lines
2.4 KiB
TypeScript
import { Data } from "types"
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/* ------------------ Command Class ----------------- */
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export type CommandFn<T> = (data: T, initial?: boolean) => void
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/**
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* A command makes changes to some applicate state. Every command has an "undo"
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* method to reverse its changes. The apps history is a series of commands.
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*/
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export class BaseCommand<T extends any> {
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timestamp = Date.now()
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name: string
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category: string
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private undoFn: CommandFn<T>
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private doFn: CommandFn<T>
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protected restoreBeforeSelectionState: (data: T) => void
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protected restoreAfterSelectionState: (data: T) => void
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protected saveSelectionState: (data: T) => (data: T) => void
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protected manualSelection: boolean
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constructor(options: {
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do: CommandFn<T>
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undo: CommandFn<T>
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name: string
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category: string
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manualSelection?: boolean
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}) {
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this.name = options.name
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this.category = options.category
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this.doFn = options.do
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this.undoFn = options.undo
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this.manualSelection = options.manualSelection || false
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this.restoreBeforeSelectionState = () => () => {
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null
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}
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this.restoreAfterSelectionState = () => () => {
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null
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}
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}
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undo = (data: T) => {
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if (this.manualSelection) {
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this.undoFn(data)
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return
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}
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// We need to set the selection state to what it was before we after we did the command
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this.restoreAfterSelectionState(data)
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this.undoFn(data)
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this.restoreBeforeSelectionState(data)
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}
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redo = (data: T, initial = false) => {
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if (initial) {
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this.restoreBeforeSelectionState = this.saveSelectionState(data)
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} else {
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this.restoreBeforeSelectionState(data)
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}
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// We need to set the selection state to what it was before we did the command
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this.doFn(data, initial)
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if (initial) {
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this.restoreAfterSelectionState = this.saveSelectionState(data)
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}
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}
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}
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/* ---------------- Project Specific ---------------- */
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/**
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* A subclass of BaseCommand that sends events to our state. In our case, we want our actions
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* to mutate the state's data. Actions do not effect the "active states" in
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* the app.
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*/
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export default class Command extends BaseCommand<Data> {
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saveSelectionState = (data: Data) => {
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const selectedIds = new Set(data.selectedIds)
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return (data: Data) => {
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data.hoveredId = undefined
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data.pointedId = undefined
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data.selectedIds = selectedIds
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}
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}
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}
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