Add initial version of action and operation. Not working

modules/actions/flip.js

@@ -0,0 +1,64 @@
+import _ from 'lodash';
+/* Flip the provided way horizontally or vertically
+Only operates on "area" ways
+*/
+
+export function actionFlip(wayId, isVertical, projection) {
+
+    return function (graph) {
+        var targetWay = graph.entity(wayId);
+        // If the way is not an area, we will not process it
+        if (!targetWay.isArea()) {
+            // return input graph without changes
+            return graph;
+        }
+        // Obtain all of the nodes on the way
+        var nodesAndRects = _(targetWay.nodes)
+            .map(function (nodeId) {
+                return graph.entity(nodeId);
+            })
+            // and their rectangles
+            .map(function (node) {
+                return {
+                    node: node,
+                    rect: node.extent().rectangle()
+                };
+            });
+        // Obtain the left/top lonlat
+        // rectangle returned as [ lon (x) top left, lat (y) top left, lon (x) bottom right, lat (y) bottom right]
+        var leftOrTop = nodesAndRects
+            .map(function (nodeAndRect) {
+                return nodeAndRect.rect;
+            })
+            .minBy(function (rect) {
+                return isVertical ? rect[1] : rect[0];
+            });
+        // Now the same for right/bottom
+        var rightOrBottom = nodesAndRects
+            .map(function (nodeAndRect) {
+                return nodeAndRect.rect;
+            })
+            .minBy(function (rect) {
+                return isVertical ? rect[3] : rect[2];
+            });
+        // Determine the mid-point that we will flip on
+        var midPoint = rightOrBottom - leftOrTop;
+        // Iterate and aggregate
+        return nodesAndRects
+            .map(function (nodeAndRect) {
+                // Get distance from midPoint
+                var node = nodeAndRect.node;
+                var delta = isVertical ?
+                    node.loc[1] - midPoint :
+                    node.loc[0] - midPoint;
+                return isVertical ?
+                    node.move(projection.translate(0, delta)) :
+                    node.move(projection.translate(delta, 0));
+            })
+            // Chain together consecutive updates to the graph for each updated node and return
+            .reduce(function (accGraph, value) {
+                return accGraph.replace(value);
+            }, graph);
+
+    };
+}

modules/operations/flip.js

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+import { t } from '../util/locale';
+import { actionFlip } from '../actions/index';
+
+
+export function operationFlip(selectedIDs, context) {
+    var entityId = selectedIDs[0];
+
+    var operation = function() {
+        context.perform(
+            actionFlip(entityId),
+            t('operations.flip.annotation')
+        );
+    };
+
+
+    operation.available = function() {
+        return selectedIDs.length === 1 &&
+            context.geometry(entityId) === 'area';
+    };
+
+
+    operation.disabled = function() {
+        return false;
+    };
+
+
+    operation.tooltip = function() {
+        return t('operations.flip.description');
+    };
+
+
+    operation.id = 'flip';
+    operation.keys = [t('operations.flip.key')];
+    operation.title = t('operations.flip.title');
+
+
+    return operation;
+}