Add Downgrade operation to remove most tags from features but retain address and building tags instead of immediate deletion

modules/modes/select.js

@@ -241,15 +241,19 @@ export function modeSelect(context, selectedIDs) {
 
         var operations = Object.values(Operations)
             .map(function(o) { return o(selectedIDs, context); })
-            .filter(function(o) { return o.available() && o.id !== 'delete'; });
+            .filter(function(o) { return o.available() && o.id !== 'delete' && o.id !== 'downgrade'; });
+
+        var downgradeOperation = Operations.operationDowngrade(selectedIDs, context);
+        // don't allow delete if downgrade is available
+        var lastOperation = downgradeOperation.available() ? downgradeOperation : Operations.operationDelete(selectedIDs, context);
 
         // deprecation warning - Radial Menu to be removed in iD v3
         var isRadialMenu = context.storage('edit-menu-style') === 'radial';
         if (isRadialMenu) {
             operations = operations.slice(0,7);
-            operations.unshift(Operations.operationDelete(selectedIDs, context));
+            operations.unshift(lastOperation);
         } else {
-            operations.push(Operations.operationDelete(selectedIDs, context));
+            operations.push(lastOperation);
         }
 
         operations.forEach(function(operation) {

modules/operations/downgrade.js

@@ -0,0 +1,135 @@
+import { actionChangeTags } from '../actions';
+import { behaviorOperation } from '../behavior';
+import { modeSelect } from '../modes';
+import { t } from '../util/locale';
+import { uiCmd } from '../ui';
+
+
+export function operationDowngrade(selectedIDs, context) {
+
+    var affectedFeatureCount = 0;
+    var downgradeType;
+
+    setDowngradeTypeForEntityIDs();
+
+    var multi = affectedFeatureCount === 1 ? 'single' : 'multiple';
+
+    function setDowngradeTypeForEntityIDs() {
+        for (var i in selectedIDs) {
+            var entityID = selectedIDs[i];
+            var type = downgradeTypeForEntityID(entityID);
+            if (type) {
+                affectedFeatureCount += 1;
+                if (downgradeType && type !== downgradeType) {
+                    downgradeType = 'building_address';
+                } else {
+                    downgradeType = type;
+                }
+            }
+        }
+    }
+
+    function downgradeTypeForEntityID(entityID) {
+        var graph = context.graph();
+        var entity = graph.entity(entityID);
+        var preset = context.presets().match(entity, graph);
+
+        if (preset.isFallback()) return null;
+
+        if (entity.type === 'node' &&
+            preset.id !== 'address' &&
+            Object.keys(entity.tags).some(function(key) {
+                return key.match(/^addr:.{1,}/);
+            })) {
+
+            return 'address';
+        }
+        if (entity.geometry(graph) === 'area' &&
+            entity.tags.building &&
+            !preset.tags.building) {
+
+            return 'building';
+        }
+
+        return null;
+    }
+
+    var buildingKeysToKeep = ['architect', 'building', 'height', 'layer', 'source', 'type', 'wheelchair'];
+    var addressKeysToKeep = ['source'];
+
+    var operation = function () {
+        context.perform(function(graph) {
+
+            for (var i in selectedIDs) {
+                var entityID = selectedIDs[i];
+                var type = downgradeTypeForEntityID(entityID);
+                if (!type) continue;
+
+                var tags = Object.assign({}, graph.entity(entityID).tags);  // shallow copy
+                for (var key in tags) {
+                    if (type === 'address' && addressKeysToKeep.indexOf(key) !== -1) continue;
+                    if (type === 'building') {
+                        if (buildingKeysToKeep.indexOf(key) !== -1 ||
+                            key.match(/^building:.{1,}/) ||
+                            key.match(/^roof:.{1,}/)) continue;
+                    }
+                    // keep address tags for buildings too
+                    if (key.match(/^addr:.{1,}/)) continue;
+
+                    delete tags[key];
+                }
+                graph = actionChangeTags(entityID, tags)(graph);
+            }
+            return graph;
+        }, operation.annotation());
+
+        // refresh the select mode to enable the delete operation
+        context.enter(modeSelect(context, selectedIDs));
+    };
+
+
+    operation.available = function () {
+        return downgradeType;
+    };
+
+
+    operation.disabled = function () {
+        var reason;
+        if (selectedIDs.some(hasWikidataTag)) {
+            reason = 'has_wikidata_tag';
+        }
+        function hasWikidataTag(id) {
+            var entity = context.entity(id);
+            return entity.tags.wikidata && entity.tags.wikidata.trim().length > 0;
+        }
+        return reason;
+    };
+
+
+    operation.tooltip = function () {
+        var disable = operation.disabled();
+        return disable ?
+            t('operations.downgrade.' + disable + '.' + multi) :
+            t('operations.downgrade.description.' + downgradeType);
+    };
+
+
+    operation.annotation = function () {
+        var suffix;
+        if (downgradeType === 'building_address') {
+            suffix = 'multiple';
+        } else {
+            suffix = downgradeType + '.' + multi;
+        }
+        return t('operations.downgrade.annotation.' + suffix, { n: affectedFeatureCount});
+    };
+
+
+    operation.id = 'downgrade';
+    operation.keys = [uiCmd('⌘⌫'), uiCmd('⌘⌦'), uiCmd('⌦')];
+    operation.title = t('operations.downgrade.title');
+    operation.behavior = behaviorOperation(context).which(operation);
+
+
+    return operation;
+}

modules/operations/index.js

@@ -2,6 +2,7 @@ export { operationCircularize } from './circularize';
 export { operationContinue } from './continue';
 export { operationDelete } from './delete';
 export { operationDisconnect } from './disconnect';
+export { operationDowngrade } from './downgrade';
 export { operationMerge } from './merge';
 export { operationMove } from './move';
 export { operationOrthogonalize } from './orthogonalize';