Add an internal utility hook for handling async values.

Signed-off-by: Eric Peterson <ericpeterson@spotify.com>
2021-12-30 14:50:33 +01:00
parent 631807c5c5
commit edfb46bc71
1 changed files with 69 additions and 0 deletions
@@ -0,0 +1,69 @@
+/*
+ * Copyright 2021 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { useRef } from 'react';
+import { useAsyncFn, useDebounce } from 'react-use';
+
+/**
+ * Utility hook for either asynchronously loading filter values from a given
+ * function or synchronously providing a given list of default values.
+ */
+export const useAsyncFilterValues = (
+  fn: ((partial: string) => Promise<string[]>) | undefined,
+  inputValue: string,
+  defaultValues: string[] = [],
+  debounce: number = 250,
+) => {
+  const valuesMemo = useRef<Record<string, string[]>>({});
+  const definiteFn = fn || (() => Promise.resolve([]));
+
+  const [state, callback] = useAsyncFn(definiteFn, [inputValue], {
+    loading: true,
+  });
+
+  // Do not invoke the given function more than necessary.
+  useDebounce(
+    () => {
+      // Performance optimization: only invoke the callback once per inputValue
+      // for the lifetime of the hook/component.
+      if (valuesMemo.current[inputValue] === undefined) {
+        callback(inputValue).then(values => {
+          valuesMemo.current[inputValue] = values;
+        });
+      }
+    },
+    debounce,
+    [callback, inputValue],
+  );
+
+  // Immediately return the default values if they are provided.
+  if (defaultValues.length) {
+    return {
+      loading: false,
+      value: defaultValues,
+    };
+  }
+
+  // Immediately return a memoized value if it is set.
+  if (valuesMemo.current[inputValue] !== undefined) {
+    return {
+      loading: false,
+      value: valuesMemo.current[inputValue],
+    };
+  }
+
+  return state;
+};