Add a keybinding behavior for operations

modules/behavior/index.js

@@ -8,6 +8,7 @@ export { behaviorEdit } from './edit';
 export { behaviorHash } from './hash';
 export { behaviorHover } from './hover';
 export { behaviorLasso } from './lasso';
+export { behaviorOperation } from './operation';
 export { behaviorPaste } from './paste';
 export { behaviorSelect } from './select';
 export { behaviorTail } from './tail';

modules/behavior/operation.js

@@ -0,0 +1,40 @@
+import * as d3 from 'd3';
+import { d3keybinding } from '../lib/d3.keybinding.js';
+
+
+/* Creates a keybinding behavior for an operation */
+export function behaviorOperation(context) {
+    var which, keybinding;
+
+
+    var behavior = function () {
+        if (which) {
+            keybinding = d3keybinding('behavior.key.' + which.id);
+            keybinding.on(which.keys, function() {
+                d3.event.preventDefault();
+                if (!(context.inIntro() || which.disabled())) {
+                    which();
+                }
+            });
+            d3.select(document).call(keybinding);
+        }
+        return behavior;
+    };
+
+
+    behavior.off = function() {
+        if (keybinding) {
+            d3.select(document).call(keybinding.off);
+        }
+    };
+
+
+    behavior.which = function (_) {
+        if (!arguments.length) return which;
+        which = _;
+        return behavior;
+    };
+
+
+    return behavior;
+}