Use Debouncer in document search.

packages/documentsearch/package.json

@@ -32,6 +32,7 @@
     "@jupyterlab/cells": "^1.0.0-alpha.7",
     "@jupyterlab/codeeditor": "^1.0.0-alpha.6",
     "@jupyterlab/codemirror": "^1.0.0-alpha.6",
+    "@jupyterlab/coreutils": "^3.0.0-alpha.6",
     "@jupyterlab/fileeditor": "^1.0.0-alpha.6",
     "@jupyterlab/notebook": "^1.0.0-alpha.7",
     "@phosphor/coreutils": "^1.3.0",

packages/documentsearch/src/searchoverlay.tsx

@@ -4,6 +4,7 @@ import { IDisplayState } from './interfaces';
 import { SearchInstance } from './searchinstance';
 
 import { ReactWidget, UseSignal } from '@jupyterlab/apputils';
+import { Debouncer } from '@jupyterlab/coreutils';
 import { Signal } from '@phosphor/signaling';
 import { Widget } from '@phosphor/widgets';
 import * as React from 'react';
@@ -252,7 +253,7 @@ class SearchOverlay extends React.Component<
   private _onSearchChange(event: React.ChangeEvent) {
     const searchText = (event.target as HTMLInputElement).value;
     this.setState({ searchText: searchText });
-    this._debouncedStartSearch(true, searchText);
+    void this._debouncedStartSearch.invoke();
   }
 
   private _onReplaceChange(event: React.ChangeEvent) {
@@ -312,24 +313,6 @@ class SearchOverlay extends React.Component<
     this.props.onEndSearch();
   }
 
-  private _debounce(func: Function, wait: number) {
-    const context = this;
-    let timeout: number;
-    return function(...args: any[]) {
-      const later = function() {
-        timeout = null;
-        return func.apply(context, args);
-      };
-      clearTimeout(timeout);
-      timeout = setTimeout(later, wait);
-    };
-  }
-
-  private _debouncedStartSearch = this._debounce(
-    this._executeSearch.bind(this),
-    100
-  );
-
   private _onReplaceToggled() {
     this.setState({
       replaceEntryShown: !this.state.replaceEntryShown
@@ -430,6 +413,10 @@ class SearchOverlay extends React.Component<
       </div>
     ];
   }
+
+  private _debouncedStartSearch = new Debouncer(() => {
+    this._executeSearch(true, this.state.searchText);
+  }, 100);
 }
 
 export function createSearchOverlay(

packages/documentsearch/tsconfig.json

@@ -23,6 +23,9 @@
     },
     {
       "path": "../notebook"
+    },
+    {
+      "path": "../coreutils"
     }
   ]
 }