Add Array.findLast and Array.findLastIndex bindings (#7503)

* Add `Array.findLast`, `Array.findLastWithIndex`, `Array.findLastIndex`, `Array.findLastIndexWithIndex` and `Array.findLastIndexOpt` bindings

* Add `TypedArray.findLast`, `TypedArray.findLastWithIndex`, `TypedArray.findLastIndex` and `TypedArray.findLastIndexWithIndex`

* Add CHANGELOG

* Update expected completions

Author: mediremi

CHANGELOG.md

@@ -15,6 +15,7 @@
 #### :rocket: New Feature
 
 - Add `RegExp.flags`. https://github.com/rescript-lang/rescript/pull/7461
+- Add `Array.findLast`, `Array.findLastWithIndex`, `Array.findLastIndex`, `Array.findLastIndexWithIndex` and `Array.findLastIndexOpt`. https://github.com/rescript-lang/rescript/pull/7503
 
 #### :bug: Bug fix
 

lib/es6/Stdlib_Array.js

@@ -106,6 +106,14 @@ function findIndexOpt(array, finder) {
 
 }
 
+function findLastIndexOpt(array, finder) {
+  let index = array.findLastIndex(finder);
+  if (index !== -1) {
+    return index;
+  }
+  
+}
+
 function swapUnsafe(xs, i, j) {
   let tmp = xs[i];
   xs[i] = xs[j];
@@ -182,6 +190,7 @@ export {
   reduceRight,
   reduceRightWithIndex,
   findIndexOpt,
+  findLastIndexOpt,
   filterMap,
   keepSome,
   toShuffled,

lib/js/Stdlib_Array.js

@@ -106,6 +106,14 @@ function findIndexOpt(array, finder) {
 
 }
 
+function findLastIndexOpt(array, finder) {
+  let index = array.findLastIndex(finder);
+  if (index !== -1) {
+    return index;
+  }
+  
+}
+
 function swapUnsafe(xs, i, j) {
   let tmp = xs[i];
   xs[i] = xs[j];
@@ -181,6 +189,7 @@ exports.reduceWithIndex = reduceWithIndex;
 exports.reduceRight = reduceRight;
 exports.reduceRightWithIndex = reduceRightWithIndex;
 exports.findIndexOpt = findIndexOpt;
+exports.findLastIndexOpt = findLastIndexOpt;
 exports.filterMap = filterMap;
 exports.keepSome = keepSome;
 exports.toShuffled = toShuffled;

runtime/Stdlib_Array.res

@@ -169,9 +169,15 @@ let lastIndexOfOpt = (arr, item) =>
 @send external find: (array<'a>, 'a => bool) => option<'a> = "find"
 @send external findWithIndex: (array<'a>, ('a, int) => bool) => option<'a> = "find"
 
+@send external findLast: (t<'a>, 'a => bool) => option<'a> = "findLast"
+@send external findLastWithIndex: (t<'a>, ('a, int) => bool) => option<'a> = "findLast"
+
 @send external findIndex: (array<'a>, 'a => bool) => int = "findIndex"
 @send external findIndexWithIndex: (array<'a>, ('a, int) => bool) => int = "findIndex"
 
+@send external findLastIndex: (t<'a>, 'a => bool) => int = "findLastIndex"
+@send external findLastIndexWithIndex: (t<'a>, ('a, int) => bool) => int = "findLastIndex"
+
 @send external forEach: (array<'a>, 'a => unit) => unit = "forEach"
 @send external forEachWithIndex: (array<'a>, ('a, int) => unit) => unit = "forEach"
 
@@ -205,6 +211,12 @@ let findIndexOpt = (array: array<'a>, finder: 'a => bool): option<int> =>
   | index => Some(index)
   }
 
+let findLastIndexOpt = (array: array<'a>, finder: 'a => bool): option<int> =>
+  switch findLastIndex(array, finder) {
+  | -1 => None
+  | index => Some(index)
+  }
+
 let swapUnsafe = (xs, i, j) => {
   let tmp = getUnsafe(xs, i)
   setUnsafe(xs, i, getUnsafe(xs, j))

runtime/Stdlib_Array.resi

@@ -720,6 +720,42 @@ array
 @send
 external findWithIndex: (array<'a>, ('a, int) => bool) => option<'a> = "find"
 
+/**
+`findLast(array, checker)` returns the last element of `array` where the provided `checker` function returns true.
+
+See [`Array.findLast`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/findLast) on MDN.
+
+## Examples
+
+```rescript
+let array = [1, 2, 3]
+
+array
+->Array.findLast(item => item > 0)
+->assertEqual(Some(3))
+```
+*/
+@send
+external findLast: (array<'a>, 'a => bool) => option<'a> = "findLast"
+
+/**
+`findLastWithIndex(array, checker)` returns the last element of `array` where the provided `checker` function returns true.
+
+See [`Array.findLast`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/findLast) on MDN.
+
+## Examples
+
+```rescript
+let array = [1, 2, 3]
+
+array
+->Array.findLastWithIndex((item, index) => index < 2 && item > 0)
+->assertEqual(Some(2))
+```
+*/
+@send
+external findLastWithIndex: (array<'a>, ('a, int) => bool) => option<'a> = "findLast"
+
 /**
 `findIndex(array, checker)` returns the index of the first element of `array` where the provided `checker` function returns true.
 
@@ -769,6 +805,55 @@ assertEqual(isTypeScriptFirst, -1)
 @send
 external findIndexWithIndex: (array<'a>, ('a, int) => bool) => int = "findIndex"
 
+/**
+`findLastIndex(array, checker)` returns the index of the last element of `array` where the provided `checker` function returns true.
+
+Returns `-1` if the item does not exist. Consider using `Array.findLastIndexOpt` if you want an option instead (where `-1` would be `None`).
+
+See [`Array.findLastIndex`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/findLastIndex) on MDN.
+
+## Examples
+
+```rescript
+type languages = ReScript | TypeScript | JavaScript
+
+let array = [ReScript, JavaScript, ReScript]
+
+array
+->Array.findLastIndex(item => item == ReScript)
+->assertEqual(2)
+
+array->Array.findLastIndex(item => item == TypeScript)
+->assertEqual(-1)
+```
+*/
+@send
+external findLastIndex: (array<'a>, 'a => bool) => int = "findLastIndex"
+
+/**
+`findLastIndexWithIndex(array, checker)` returns the index of the last element of `array` where the provided `checker` function returns true.
+
+Returns `-1` if the item does not exist. Consider using `Array.findLastIndexOpt` if you want an option instead (where `-1` would be `None`).
+
+See [`Array.findLastIndex`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/findLastIndex) on MDN.
+
+## Examples
+
+```rescript
+type languages = ReScript | TypeScript | JavaScript
+
+let array = [ReScript, JavaScript, JavaScript, ReScript]
+
+let isReScriptLast = array->Array.findLastIndexWithIndex((item, index) => index === 3 && item == ReScript)
+let isTypeScriptLast = array->Array.findLastIndexWithIndex((item, index) => index === 3 && item == TypeScript)
+
+assertEqual(isReScriptLast, 3)
+assertEqual(isTypeScriptLast, -1)
+```
+*/
+@send
+external findLastIndexWithIndex: (array<'a>, ('a, int) => bool) => int = "findLastIndex"
+
 /**
 `forEach(array, fn)` runs the provided `fn` on every element of `array`.
 
@@ -1064,6 +1149,25 @@ array
 */
 let findIndexOpt: (array<'a>, 'a => bool) => option<int>
 
+/**
+`findIndexOpt(array, checker)` returns the index of the last element of `array` where the provided `checker` function returns true.
+
+Returns `None` if no item matches.
+
+See [`Array.findLastIndex`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/findLastIndex) on MDN.
+
+## Examples
+
+```rescript
+let array = ["hello", "world", "!"]
+
+array
+->Array.findLastIndexOpt(item => item->String.includes("o"))
+->assertEqual(Some(1))
+```
+*/
+let findLastIndexOpt: (array<'a>, 'a => bool) => option<int>
+
 /**
 `toReversed(array)` creates a new array with all items from `array` in reversed order.
 

runtime/Stdlib_TypedArray.res

@@ -59,9 +59,15 @@ external copyWithin: (t<'a>, ~target: int, ~start: int, ~end: int) => array<'a>
 @send external find: (t<'a>, 'a => bool) => option<'a> = "find"
 @send external findWithIndex: (t<'a>, ('a, int) => bool) => option<'a> = "find"
 
+@send external findLast: (t<'a>, 'a => bool) => option<'a> = "findLast"
+@send external findLastWithIndex: (t<'a>, ('a, int) => bool) => option<'a> = "findLast"
+
 @send external findIndex: (t<'a>, 'a => bool) => int = "findIndex"
 @send external findIndexWithIndex: (t<'a>, ('a, int) => bool) => int = "findIndex"
 
+@send external findLastIndex: (t<'a>, 'a => bool) => int = "findLastIndex"
+@send external findLastIndexWithIndex: (t<'a>, ('a, int) => bool) => int = "findLastIndex"
+
 @send external forEach: (t<'a>, 'a => unit) => unit = "forEach"
 @send external forEachWithIndex: (t<'a>, ('a, int) => unit) => unit = "forEach"
 

tests/analysis_tests/tests/src/expected/Completion.res.txt

@@ -64,6 +64,18 @@ Path Array.
     "tags": [],
     "detail": "(array<'a>, 'a => option<'b>) => array<'b>",
     "documentation": {"kind": "markdown", "value": "\n`filterMap(array, fn)`\n\nCalls `fn` for each element and returns a new array containing results of the `fn` calls which are not `None`.\n\n## Examples\n\n```rescript\n[\"Hello\", \"Hi\", \"Good bye\"]\n->Array.filterMap(item =>\n  switch item {\n  | \"Hello\" => Some(item->String.length)\n  | _ => None\n  }\n)\n->assertEqual([5])\n\n[1, 2, 3, 4, 5, 6]\n->Array.filterMap(n => mod(n, 2) == 0 ? Some(n * n) : None)\n->assertEqual([4, 16, 36])\n\nArray.filterMap([1, 2, 3, 4, 5, 6], _ => None)->assertEqual([])\n\nArray.filterMap([], n => mod(n, 2) == 0 ? Some(n * n) : None)->assertEqual([])\n```\n"}
+  }, {
+    "label": "findLastWithIndex",
+    "kind": 12,
+    "tags": [],
+    "detail": "(array<'a>, ('a, int) => bool) => option<'a>",
+    "documentation": {"kind": "markdown", "value": "\n`findLastWithIndex(array, checker)` returns the last element of `array` where the provided `checker` function returns true.\n\nSee [`Array.findLast`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/findLast) on MDN.\n\n## Examples\n\n```rescript\nlet array = [1, 2, 3]\n\narray\n->Array.findLastWithIndex((item, index) => index < 2 && item > 0)\n->assertEqual(Some(2))\n```\n"}
+  }, {
+    "label": "findLast",
+    "kind": 12,
+    "tags": [],
+    "detail": "(array<'a>, 'a => bool) => option<'a>",
+    "documentation": {"kind": "markdown", "value": "\n`findLast(array, checker)` returns the last element of `array` where the provided `checker` function returns true.\n\nSee [`Array.findLast`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/findLast) on MDN.\n\n## Examples\n\n```rescript\nlet array = [1, 2, 3]\n\narray\n->Array.findLast(item => item > 0)\n->assertEqual(Some(3))\n```\n"}
   }, {
     "label": "shift",
     "kind": 12,
@@ -178,6 +190,12 @@ Path Array.
     "tags": [],
     "detail": "(array<'a>, 'a) => bool",
     "documentation": {"kind": "markdown", "value": "\n`includes(array, item)` checks whether `array` includes `item`, by doing a [strict check for equality](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Strict_equality).\n\nSee [`Array.includes`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/includes) on MDN.\n\n## Examples\n\n```rescript\n[1, 2]->Array.includes(1)->assertEqual(true)\n[1, 2]->Array.includes(3)->assertEqual(false)\n\n[{\"language\": \"ReScript\"}]\n->Array.includes({\"language\": \"ReScript\"})\n->assertEqual(false) // false, because of strict equality\n```\n"}
+  }, {
+    "label": "findLastIndex",
+    "kind": 12,
+    "tags": [],
+    "detail": "(array<'a>, 'a => bool) => int",
+    "documentation": {"kind": "markdown", "value": "\n`findLastIndex(array, checker)` returns the index of the last element of `array` where the provided `checker` function returns true.\n\nReturns `-1` if the item does not exist. Consider using `Array.findLastIndexOpt` if you want an option instead (where `-1` would be `None`).\n\nSee [`Array.findLastIndex`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/findLastIndex) on MDN.\n\n## Examples\n\n```rescript\ntype languages = ReScript | TypeScript | JavaScript\n\nlet array = [ReScript, JavaScript, ReScript]\n\narray\n->Array.findLastIndex(item => item == ReScript)\n->assertEqual(2)\n\narray->Array.findLastIndex(item => item == TypeScript)\n->assertEqual(-1)\n```\n"}
   }, {
     "label": "fromInitializer",
     "kind": 12,
@@ -298,6 +316,12 @@ Path Array.
     "tags": [],
     "detail": "array<'a> => unit",
     "documentation": {"kind": "markdown", "value": "\n`reverse(array)` reverses the order of the items in `array`.\n\nBeware this will *mutate* the array.\n\nSee [`Array.reverse`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/reverse) on MDN.\n\n## Examples\n\n```rescript\nlet someArray = [\"hi\", \"hello\"]\nsomeArray->Array.reverse\n\nsomeArray->assertEqual([\"hello\", \"hi\"])\n```\n"}
+  }, {
+    "label": "findLastIndexWithIndex",
+    "kind": 12,
+    "tags": [],
+    "detail": "(array<'a>, ('a, int) => bool) => int",
+    "documentation": {"kind": "markdown", "value": "\n`findLastIndexWithIndex(array, checker)` returns the index of the last element of `array` where the provided `checker` function returns true.\n\nReturns `-1` if the item does not exist. Consider using `Array.findLastIndexOpt` if you want an option instead (where `-1` would be `None`).\n\nSee [`Array.findLastIndex`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/findLastIndex) on MDN.\n\n## Examples\n\n```rescript\ntype languages = ReScript | TypeScript | JavaScript\n\nlet array = [ReScript, JavaScript, JavaScript, ReScript]\n\nlet isReScriptLast = array->Array.findLastIndexWithIndex((item, index) => index === 3 && item == ReScript)\nlet isTypeScriptLast = array->Array.findLastIndexWithIndex((item, index) => index === 3 && item == TypeScript)\n\nassertEqual(isReScriptLast, 3)\nassertEqual(isTypeScriptLast, -1)\n```\n"}
   }, {
     "label": "getUnsafe",
     "kind": 12,
@@ -520,6 +544,12 @@ Path Array.
     "tags": [],
     "detail": "(array<'a>, int) => unit",
     "documentation": {"kind": "markdown", "value": "\n`removeInPlace(array, index)` removes the item at the specified `index` from `array`.\n\nBeware this will *mutate* the array.\n\n## Examples\n\n```rescript\nlet array = []\narray->Array.removeInPlace(0)\nassertEqual(array, []) // Removing from an empty array does nothing\n\nlet array2 = [\"Hello\", \"Hi\", \"Good bye\"]\narray2->Array.removeInPlace(1)\nassertEqual(array2, [\"Hello\", \"Good bye\"]) // Removes the item at index 1\n```\n "}
+  }, {
+    "label": "findLastIndexOpt",
+    "kind": 12,
+    "tags": [],
+    "detail": "(array<'a>, 'a => bool) => option<int>",
+    "documentation": {"kind": "markdown", "value": "\n`findIndexOpt(array, checker)` returns the index of the last element of `array` where the provided `checker` function returns true.\n\nReturns `None` if no item matches.\n\nSee [`Array.findLastIndex`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/findLastIndex) on MDN.\n\n## Examples\n\n```rescript\nlet array = [\"hello\", \"world\", \"!\"]\n\narray\n->Array.findLastIndexOpt(item => item->String.includes(\"o\"))\n->assertEqual(Some(1))\n```\n"}
   }, {
     "label": "pushMany",
     "kind": 12,