Add support for clearing selection

src/compile/selection/transforms/clear.ts

@@ -1,16 +1,32 @@
 import {TUPLE} from '..';
+import {selector as parseSelector} from 'vega-event-selector';
 import {TransformCompiler} from './transforms';
 
+const CLEAR_DATA_SIGNALS = [TUPLE, '_toggle'];
+const CLEAR_VISUAL_SIGNALS = ['_x', '_y'];
+
+const CLEAR_SIGNALS = [CLEAR_DATA_SIGNALS, CLEAR_VISUAL_SIGNALS];
+const CLEAR_UPDATE = ['null', '[0, 0]'];
+
 const clear: TransformCompiler = {
   has: selCmpt => {
     return selCmpt.clear;
   },
 
   signals: (model, selCmpt, signals) => {
-    const tupleIdx = signals.findIndex(i => i.name === selCmpt.name + TUPLE);
-    signals[tupleIdx].on.push({
-      events: [{source: 'scope', type: selCmpt.clear}],
-      update: 'null'
+    let events = parseSelector(selCmpt.clear, 'scope');
+    CLEAR_SIGNALS.forEach((signal, k) => {
+      for (let i = 0; i < signal.length; i++) {
+        const idx = signals.findIndex(n => n.name === selCmpt.name + signal[i]);
+        if (idx !== -1) {
+          signals[idx].on = signals[idx].on
+            ? signals[idx].on.concat({
+                events: events,
+                update: CLEAR_UPDATE[k]
+              })
+            : [{events: events, update: CLEAR_UPDATE[k]}];
+        }
+      }
     });
     return signals;
   }

src/compile/selection/transforms/transforms.ts

@@ -1,7 +1,6 @@
 import {NewSignal, Signal} from 'vega';
 import {SelectionComponent} from '..';
 import {SelectionDef} from '../../../selection';
-import {Dict} from '../../../util';
 import {Model} from '../../model';
 import {UnitModel} from '../../unit';
 import clear from './clear';
@@ -22,21 +21,12 @@ export interface TransformCompiler {
   marks?: (model: UnitModel, selCmpt: SelectionComponent, marks: any[]) => any[];
 }
 
-const compilers: Dict<TransformCompiler> = {
-  project,
-  toggle,
-  scales,
-  translate,
-  zoom,
-  inputs,
-  nearest,
-  clear
-};
+const compilers: Array<TransformCompiler> = [project, toggle, scales, translate, zoom, inputs, nearest, clear];
 
 export function forEachTransform(selCmpt: SelectionComponent, cb: (tx: TransformCompiler) => void) {
-  for (const t in compilers) {
-    if (compilers[t].has(selCmpt)) {
-      cb(compilers[t]);
+  for (const t of compilers) {
+    if (t.has(selCmpt)) {
+      cb(t);
     }
   }
 }

src/selection.ts

@@ -58,15 +58,14 @@ export interface BaseSelectionDef {
 
 export interface SingleSelectionConfig extends BaseSelectionDef {
   /**
-   * Controls clearing selections. Can be `true`, `false`, or a `string` that is
-   * one of the [Supported Event Types](https://vega.github.io/vega/docs/event-streams/).
+   * Controls clearing selections. Can be `true`, `false`, or an [EventStream](https://vega.github.io/vega/docs/event-streams/).
    *
    * __Default value:__ `true`, which corresponds to `dblclick` (i.e.
    * user doubleclick clears current selection).
    *
    * See the [TODO: clear] documentation for more information.
    */
-  clear?: string | boolean;
+  clear?: EventStream | boolean;
   /**
    * Establish a two-way binding between a single selection and input elements
    * (also known as dynamic query widgets). A binding takes the form of
@@ -93,15 +92,14 @@ export interface SingleSelectionConfig extends BaseSelectionDef {
 
 export interface MultiSelectionConfig extends BaseSelectionDef {
   /**
-   * Controls clearing selections. Can be `true`, `false`, or a `string` that is
-   * one of the [Supported Event Types](https://vega.github.io/vega/docs/event-streams/).
+   * Controls clearing selections. Can be `true`, `false`, or an [EventStream](https://vega.github.io/vega/docs/event-streams/).
    *
    * __Default value:__ `true`, which corresponds to `dblclick` (i.e.
    * user doubleclick clears current selection).
    *
    * See the [TODO: clear] documentation for more information.
    */
-  clear?: string | boolean;
+  clear?: EventStream | boolean;
 
   /**
    * Controls whether data values should be toggled or only ever inserted into
@@ -171,15 +169,14 @@ export interface BrushConfig {
 
 export interface IntervalSelectionConfig extends BaseSelectionDef {
   /**
-   * Controls clearing selections. Can be `true`, `false`, or a `string` that is
-   * one of the [Supported Event Types](https://vega.github.io/vega/docs/event-streams/).
+   * Controls clearing selections. Can be `true`, `false`, or an [EventStream](https://vega.github.io/vega/docs/event-streams/).
    *
    * __Default value:__ `true`, which corresponds to `dblclick` (i.e.
    * user doubleclick clears current selection).
    *
    * See the [TODO: clear] documentation for more information.
    */
-  clear?: string | boolean;
+  clear?: EventStream | boolean;
   /**
    * When truthy, allows a user to interactively move an interval selection
    * back-and-forth. Can be `true`, `false` (to disable panning), or a
@@ -272,6 +269,7 @@ export const defaultConfig: SelectionConfig = {
   single: {
     on: 'click',
     fields: [SELECTION_ID],
+    clear: 'dblclick',
     resolve: 'global',
     empty: 'all'
   },