1 files changed, 6 insertions, 2 deletions
diff --git a/src/prelude/array.ts b/src/prelude/array.ts
index 8536e486d6..69b52fde87 100644
--- a/src/prelude/array.ts
+++ b/src/prelude/array.ts
@@ -18,8 +18,12 @@ export function erase<T>(x: T, xs: T[]): T[] {
 	return xs.filter(y => x !== y);
 }
 
-export function setDifference<T>(xs: T[], ys: T[]): T[] {
-	return xs.filter(x => !ys.includes(x));
+/**
+ * Finds the array of all elements in the first array not contained in the second array.
+ * The order of result values are determined by the first array.
+ */
+export function difference<T>(includes: T[], excludes: T[]): T[] {
+	return includes.filter(x => !excludes.includes(x));
 }
 
 export function unique<T>(xs: T[]): T[] {