gristlabs_grist-core/app/client/components/Cursor.ts

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/**
* The Cursor module contains functionality related to the cell with the cursor, i.e. a single
* currently selected cell.
*/
import BaseView from 'app/client/components/BaseView';
import * as commands from 'app/client/components/commands';
import BaseRowModel from 'app/client/models/BaseRowModel';
import {LazyArrayModel} from 'app/client/models/DataTableModel';
import type {RowId} from 'app/client/models/rowset';
import {Disposable} from 'grainjs';
import * as ko from 'knockout';
export interface CursorPos {
rowId?: RowId;
rowIndex?: number;
fieldIndex?: number;
sectionId?: number;
}
function nullAsUndefined<T>(value: T|null|undefined): T|undefined {
return value == null ? undefined : value;
}
/**
* Cursor represents the location of the cursor in the viewsection. It is maintained by BaseView,
* and implements the shared functionality related to the cursor cell.
* @param {BaseView} baseView: The BaseView object to which this Cursor belongs.
* @param {Object} optCursorPos: Optional object containing rowId and fieldIndex properties
* to which the cursor should be initialized.
*/
export class Cursor extends Disposable {
/**
* The commands closely tied to the cursor. They are active when the BaseView containing this
* Cursor has focus. Some may need to be overridden by particular views.
*/
public static editorCommands = {
// The cursor up/down commands may need to be a bit different in non-grid views.
cursorUp(this: Cursor) { this.rowIndex(this.rowIndex()! - 1); },
cursorDown(this: Cursor) { this.rowIndex(this.rowIndex()! + 1); },
cursorLeft(this: Cursor) { this.fieldIndex(this.fieldIndex() - 1); },
cursorRight(this: Cursor) { this.fieldIndex(this.fieldIndex() + 1); },
skipUp(this: Cursor) { this.rowIndex(this.rowIndex()! - 5); },
skipDown(this: Cursor) { this.rowIndex(this.rowIndex()! + 5); },
pageUp(this: Cursor) { this.rowIndex(this.rowIndex()! - 20); }, // TODO Not really pageUp
pageDown(this: Cursor) { this.rowIndex(this.rowIndex()! + 20); }, // TODO Not really pageDown
prevField(this: Cursor) { this.fieldIndex(this.fieldIndex() - 1); },
nextField(this: Cursor) { this.fieldIndex(this.fieldIndex() + 1); },
moveToFirstRecord(this: Cursor) { this.rowIndex(0); },
moveToLastRecord(this: Cursor) { this.rowIndex(Infinity); },
moveToFirstField(this: Cursor) { this.fieldIndex(0); },
moveToLastField(this: Cursor) { this.fieldIndex(Infinity); },
};
public viewData: LazyArrayModel<BaseRowModel>;
// observable with current cursor position
public currentPosition: ko.Computed<CursorPos>;
public rowIndex: ko.Computed<number|null>; // May be null when there are no rows.
public fieldIndex: ko.Observable<number>;
private _rowId: ko.Observable<RowId|null>; // May be null when there are no rows.
// The cursor's _rowId property is always fixed across data changes. When isLive is true,
// the rowIndex of the cursor is recalculated to match _rowId. When false, they will
// be out of sync.
private _isLive: ko.Observable<boolean> = ko.observable(true);
private _sectionId: ko.Computed<number>;
constructor(baseView: BaseView, optCursorPos?: CursorPos) {
super();
optCursorPos = optCursorPos || {};
this.viewData = baseView.viewData;
this._sectionId = this.autoDispose(ko.computed(() => baseView.viewSection.id()));
this._rowId = ko.observable<RowId|null>(optCursorPos.rowId || 0);
this.rowIndex = this.autoDispose(ko.computed({
read: () => {
if (!this._isLive()) { return this.rowIndex.peek(); }
const rowId = this._rowId();
return rowId == null ? null : this.viewData.clampIndex(this.viewData.getRowIndexWithSub(rowId));
},
write: (index) => {
const rowIndex = this.viewData.clampIndex(index!);
this._rowId(rowIndex == null ? null : this.viewData.getRowId(rowIndex));
},
}));
this.fieldIndex = baseView.viewSection.viewFields().makeLiveIndex(optCursorPos.fieldIndex || 0);
this.autoDispose(commands.createGroup(Cursor.editorCommands, this, baseView.viewSection.hasFocus));
// Update the section's activeRowId when the cursor's rowId changes.
this.autoDispose(this._rowId.subscribe((rowId) => baseView.viewSection.activeRowId(rowId)));
// On dispose, save the current cursor position to the section model.
this.onDispose(() => { baseView.viewSection.lastCursorPos = this.getCursorPos(); });
// calculate current position
this.currentPosition = this.autoDispose(ko.computed(() => this._isLive() ? this.getCursorPos() : {}));
}
// Returns the cursor position with rowId, rowIndex, and fieldIndex.
public getCursorPos(): CursorPos {
return {
rowId: nullAsUndefined(this._rowId()),
rowIndex: nullAsUndefined(this.rowIndex()),
fieldIndex: this.fieldIndex(),
sectionId: this._sectionId()
};
}
/**
* Moves the cursor to the given position. Only moves the row if rowId or rowIndex is valid,
* preferring rowId.
* @param cursorPos: Position as { rowId?, rowIndex?, fieldIndex? }, as from getCursorPos().
*/
public setCursorPos(cursorPos: CursorPos): void {
if (cursorPos.rowId !== undefined && this.viewData.getRowIndex(cursorPos.rowId) >= 0) {
this._rowId(cursorPos.rowId);
} else if (cursorPos.rowIndex !== undefined && cursorPos.rowIndex >= 0) {
this.rowIndex(cursorPos.rowIndex);
} else {
// Write rowIndex to itself to force an update of rowId if needed.
this.rowIndex(this.rowIndex.peek());
}
if (cursorPos.fieldIndex !== undefined) {
this.fieldIndex(cursorPos.fieldIndex);
}
}
public setLive(isLive: boolean): void {
this._isLive(isLive);
}
}