diff --git a/src/vs/base/common/arrays.ts b/src/vs/base/common/arrays.ts
index f3f8fc6a201bb44cdc5320b55f3a566b5ffea30d..bf47f5db4f91096c95608efadbe5189ac854c717 100644
--- a/src/vs/base/common/arrays.ts
+++ b/src/vs/base/common/arrays.ts
@@ -232,4 +232,10 @@ export function fill<T>(num: number, valueFn: () => T, arr: T[] = []): T[] {
 	}
 
 	return arr;
+}
+
+export function index<T>(array: T[], indexer: (t: T) => string): { [key: string]: T; } {
+	const result = Object.create(null);
+	array.forEach(t => result[indexer(t)] = t);
+	return result;
 }
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