adding tests for side updates

Author: BSd3v

dash/dash-renderer/src/actions/callbacks.ts

@@ -41,7 +41,7 @@ import {createAction, Action} from 'redux-actions';
 import {addHttpHeaders} from '../actions';
 import {notifyObservers, updateProps} from './index';
 import {CallbackJobPayload} from '../reducers/callbackJobs';
-import {handlePatch, isPatch, parsePatchProps} from './patch';
+import {parsePatchProps} from './patch';
 import {computePaths, getPath} from './paths';
 
 import {requestDependencies} from './requestDependencies';
@@ -818,12 +818,23 @@ export function executeCallback(
 
                 if (clientside_function) {
                     try {
-                        const data = await handleClientside(
+                        let data = await handleClientside(
                             dispatch,
                             clientside_function,
                             config,
                             payload
                         );
+                        // Patch methodology: always run through parsePatchProps for each output
+                        const currentLayout = getState().layout;
+                        flatten(outputs).forEach((out: any) => {
+                            const propName = cleanOutputProp(out.property);
+                            const outputPath = getPath(paths, out.id);
+                            const dataPath = [stringifyId(out.id), propName];
+                            const outputValue = path(dataPath, data);
+                            const oldProps = path(outputPath.concat(['props']), currentLayout) || {};
+                            const newProps = parsePatchProps({ [propName]: outputValue }, oldProps);
+                            data = assocPath(dataPath, newProps[propName], data);
+                        });
                         return {data, payload};
                     } catch (error: any) {
                         return {error, payload};
@@ -882,26 +893,16 @@ export function executeCallback(
                             dispatch(addHttpHeaders(newHeaders));
                         }
                         // Layout may have changed.
+                        // DRY: Always run through parsePatchProps for each output
                         const currentLayout = getState().layout;
                         flatten(outputs).forEach((out: any) => {
                             const propName = cleanOutputProp(out.property);
                             const outputPath = getPath(paths, out.id);
-                            const previousValue = path(
-                                outputPath.concat(['props', propName]),
-                                currentLayout
-                            );
                             const dataPath = [stringifyId(out.id), propName];
                             const outputValue = path(dataPath, data);
-                            if (isPatch(outputValue)) {
-                                if (previousValue === undefined) {
-                                    throw new Error('Cannot patch undefined');
-                                }
-                                data = assocPath(
-                                    dataPath,
-                                    handlePatch(previousValue, outputValue),
-                                    data
-                                );
-                            }
+                            const oldProps = path(outputPath.concat(['props']), currentLayout) || {};
+                            const newProps = parsePatchProps({ [propName]: outputValue }, oldProps);
+                            data = assocPath(dataPath, newProps[propName], data);
                         });
 
                         if (dynamic_creator) {

dash/dash-renderer/src/actions/patch.ts

@@ -175,7 +175,7 @@ export class PatchBuilder {
 
     build() {
         return {
-            __dash_patch_update: true,
+            __dash_patch_update: "__dash_patch_update",
             operations: this.operations
         };
     }
@@ -304,7 +304,7 @@ export function handlePatch<T>(previousValue: T, patchValue: any): T {
     return reducedValue;
 }
 
-export function parsePatchProps(props: any, previousProps: any): {} {
+export function parsePatchProps(props: any, previousProps: any): Record<string, any> {
     if (!is(Object, props)) {
         return props;
     }