diff options
| -rw-r--r-- | CHANGELOG.md | 2 | ||||
| -rw-r--r-- | src/ffi.js | 4 | ||||
| -rw-r--r-- | src/gleam/javascript/array.gleam | 3 | ||||
| -rw-r--r-- | test/gleam/javascript/array_test.gleam | 17 |
4 files changed, 25 insertions, 1 deletions
diff --git a/CHANGELOG.md b/CHANGELOG.md index 04012f9..07d70c7 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -3,4 +3,4 @@ ## Unreleased - The `array` module was created with the `Array(element)` type and `to_list`, - `from_list`, `map`, and `length` functions. + `from_list`, `map`, `fold`, and `length` functions. @@ -9,3 +9,7 @@ export function map(thing, fn) { export function length(thing) { return thing.length; } + +export function reduce(thing, acc, fn) { + return thing.reduce(fn, acc); +} diff --git a/src/gleam/javascript/array.gleam b/src/gleam/javascript/array.gleam index 6c4819e..20d12d1 100644 --- a/src/gleam/javascript/array.gleam +++ b/src/gleam/javascript/array.gleam @@ -11,3 +11,6 @@ pub external fn length(Array(element)) -> Int = pub external fn map(Array(a), fn(a) -> b) -> Array(b) = "../../ffi.js" "map" + +pub external fn fold(Array(e), a, fn(a, e) -> a) -> a = + "../../ffi.js" "reduce" diff --git a/test/gleam/javascript/array_test.gleam b/test/gleam/javascript/array_test.gleam index 2f149a5..5bf52db 100644 --- a/test/gleam/javascript/array_test.gleam +++ b/test/gleam/javascript/array_test.gleam @@ -31,3 +31,20 @@ pub fn map_test() { |> array.map(fn(a) { a + 1 }) |> array.to_list } + +pub fn fold_test() { + assert [] = + [] + |> array.from_list + |> array.fold([], fn(a, e) { [e, ..a] }) + + assert [4, 3, 2, 1] = + [1, 2, 3, 4] + |> array.from_list + |> array.fold([], fn(a, e) { [e, ..a] }) + + assert [1, 2, 3, 4] = + [4, 3, 2, 1] + |> array.from_list + |> array.fold([], fn(a, e) { [e, ..a] }) +} |