fixed error prettier

Author: François Andrieux

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

@@ -233,13 +233,27 @@ export const getReadyCallbacks = (
         }
     }
 
+    // Ramda.JS `difference` function is slow because it compares objects entirely
+    // This cause the following `filter` to be exponentially slow as the number of inputs or outputs grow
+    // We can optimize this by comparing only the `id+prop` part of the inputs & outputs.
+    // Original difference takes 380ms on average to compute difference between 200 inputs and 1 output.
+    // The following function takes 1-2ms on average.
+    const differenceBasedOnId = (inputs: any[], outputs: any[]): any[] =>
+        inputs.filter(
+            input =>
+                !outputs.some(
+                    output =>
+                        combineIdAndProp(input) === combineIdAndProp(output)
+                )
+        );
+
     // Find `requested` callbacks that do not depend on a outstanding output (as either input or state)
     // Outputs which overlap an input do not count as an outstanding output
     return filter(
         cb =>
             all<ILayoutCallbackProperty>(
                 cbp => !outputsMap[combineIdAndProp(cbp)],
-                difference(
+                differenceBasedOnId(
                     flatten(cb.getInputs(paths)),
                     flatten(cb.getOutputs(paths))
                 )

dash/dash-renderer/src/observers/prioritizedCallbacks.ts

@@ -1,4 +1,4 @@
-import {find, flatten, map, partition, pluck, sort, uniq} from 'ramda';
+import {find, flatten, map, partition, sort} from 'ramda';
 
 import {IStoreState} from '../store';
 
@@ -53,13 +53,16 @@ const getStash = (
     return {allOutputs, allPropIds};
 };
 
-const getIds = (cb: ICallback, paths: any) =>
-    uniq(
-        pluck('id', [
-            ...flatten(cb.getInputs(paths)),
-            ...flatten(cb.getState(paths))
-        ])
-    );
+const getIds = (cb: ICallback, paths: any) => {
+    const items = [
+        ...flatten(cb.getInputs(paths)),
+        ...flatten(cb.getState(paths))
+    ];
+
+    const uniqueIds = new Map(items.map(item => [stringifyId(item.id), item]));
+    const uniqueItems = Array.from(uniqueIds.values());
+    return uniqueItems;
+};
 
 const observer: IStoreObserverDefinition<IStoreState> = {
     observer: async ({dispatch, getState}) => {