From 5e2b8d3be0d974f0f1e66437633a8006fc265174 Mon Sep 17 00:00:00 2001
From: naskya <m@naskya.net>
Date: Tue, 26 Mar 2024 19:43:11 +0900
Subject: [PATCH] chore: add a function to compare two arrays
---
packages/backend/src/prelude/array.ts | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/packages/backend/src/prelude/array.ts b/packages/backend/src/prelude/array.ts
index 71a24c89b7..20ffbcd339 100644
--- a/packages/backend/src/prelude/array.ts
+++ b/packages/backend/src/prelude/array.ts
@@ -3,7 +3,6 @@ import type { EndoRelation, Predicate } from "./relation.js";
/**
* Count the number of elements that satisfy the predicate
*/
-
export function countIf<T>(f: Predicate<T>, xs: T[]): number {
return xs.filter(f).length;
}
@@ -60,6 +59,21 @@ export function maximum(xs: number[]): number {
return Math.max(...xs);
}
+/**
+ * Returns if two arrays are equal
+ *
+ * examples:
+ * equal([1, 2, 3], [1, 2, 3]) === true
+ * equal([1, 2, 3], [1, 3, 2]) === false
+ * equal([1, 2, 3], [1, 2]) === false
+ */
+export function equal<T>(lhs: T[], rhs: T[]): boolean {
+ return (
+ lhs.length === rhs.length &&
+ lhs.every((value, index) => value === rhs[index])
+ );
+}
+
/**
* Splits an array based on the equivalence relation.
* The concatenation of the result is equal to the argument.