Add function.constant

This change adds a new helper to the function module.

1 files changed, 7 insertions, 0 deletions

diff --git a/test/gleam/function_test.gleam b/test/gleam/function_test.gleam
index e86beb3..1495d2a 100644
--- a/test/gleam/function_test.gleam
+++ b/test/gleam/function_test.gleam
@@ -2,6 +2,7 @@ import gleam/should
 import gleam/dynamic
 import gleam/function
 import gleam/int
+import gleam/pair
 import gleam/list
 import gleam/result
 import gleam/string
@@ -107,3 +108,9 @@ pub fn identity_test() {
   |> function.identity
   |> should.equal(#(1, 2.0))
 }
+
+pub fn always_test() {
+  #(1, 2)
+  |> pair.map_first(function.constant(42))
+  |> should.equal(#(42, 2))
+}