feat: add startSelected on select event

Author: daybrush

packages/selecto/src/SelectoManager.tsx

@@ -149,7 +149,7 @@ class Selecto extends EventEmitter<SelectoEvents> {
      * selectByClick, continueSelect, and continueSelectWithoutDeselect are not applied.
      */
     public setSelectedTargets(
-        selectedTargets: Array<HTMLElement | SVGElement>
+        selectedTargets: Array<HTMLElement | SVGElement>,
     ): SelectedTargets {
         const beforeSelected = this.selectedTargets;
         const { added, removed, prevList, list } = diff(
@@ -762,6 +762,17 @@ class Selecto extends EventEmitter<SelectoEvents> {
         const inputEvent = e.inputEvent;
         const data = e.data;
         const result = this.setSelectedTargets(selectedTargets);
+        const { added, removed, prevList, list } = diff(
+            data.startSelectedTargets,
+            selectedTargets,
+        );
+
+        const startResult = {
+            startSelected: prevList,
+            startAdded: added.map(i => list[i]),
+            startRemoved: removed.map(i => prevList[i]),
+        };
+
 
         if (isStart) {
             /**
@@ -796,6 +807,7 @@ class Selecto extends EventEmitter<SelectoEvents> {
              */
             this.emit("selectStart", {
                 ...result,
+                ...startResult,
                 rect,
                 inputEvent,
                 data: data.data,
@@ -829,6 +841,7 @@ class Selecto extends EventEmitter<SelectoEvents> {
              */
             this.emit("select", {
                 ...result,
+                ...startResult,
                 rect,
                 inputEvent,
                 data: data.data,

packages/selecto/src/types.ts

@@ -255,7 +255,7 @@ export interface SelectedTargetsWithRect extends SelectedTargets {
  * @extends Selecto.SelectedTargetsWithRect
  * @typedef
  */
-export interface OnSelect<T = Selecto> extends CurrentTarget<T>, SelectedTargetsWithRect {
+export interface OnSelectEvent<T = Selecto> extends CurrentTarget<T>, SelectedTargetsWithRect {
     /**
      * inputEvent
      */
@@ -275,11 +275,29 @@ export interface OnSelect<T = Selecto> extends CurrentTarget<T>, SelectedTargets
 }
 /**
  * @memberof Selecto
- * @extends Selecto.OnSelect
- * @extends Selecto.CurrentTarget
+ * @extends Selecto.OnSelectEvent
+ * @typedef
+ */
+export interface OnSelect<T = Selecto> extends OnSelectEvent<T> {
+    /**
+     * start selected elements
+     */
+    startSelected: Array<HTMLElement | SVGElement>;
+    /**
+     * added from start selected
+     */
+    startAdded: Array<HTMLElement | SVGElement>;
+    /**
+     * removed from start selected
+     */
+    startRemoved: Array<HTMLElement | SVGElement>;
+}
+/**
+ * @memberof Selecto
+ * @extends Selecto.OnSelectEvent
  * @typedef
  */
-export interface OnSelectEnd<T = Selecto> extends OnSelect<T>, CurrentTarget<T> {
+export interface OnSelectEnd<T = Selecto> extends OnSelectEvent<T> {
     /**
      * start selected elements
      */