update

collections/take_while.ts

@@ -5,6 +5,9 @@
  * Returns all elements in the given collection until the first element that
  * does not match the given predicate.
  *
+ * Note: If you want to process any iterable, use the new version of
+ * `takeWhile` from `@std/collections/unstable-take-while`.
+ *
  * @typeParam T The type of the array elements.
  *
  * @param array The array to take elements from.

collections/take_while_test.ts

@@ -57,6 +57,59 @@ Deno.test("takeWhile() returns the same array when all elements match the predic
   assertEquals(actual, [1, 2, 3, 4]);
 });
 
+Deno.test("(unstable) takeWhile() handles num array", () => {
+  const arr = [1, 2, 3, 4, 5, 6];
+  const actual = unstableTakeWhile(arr, (i) => i !== 4);
+
+  assertEquals(actual, [1, 2, 3]);
+});
+
+Deno.test("(unstable) takeWhile() adds two to each num in predicate", () => {
+  const arr = [1, 2, 3, 4, 5, 6];
+  const actual = unstableTakeWhile(arr, (i) => i + 2 !== 6);
+
+  assertEquals(actual, [1, 2, 3]);
+});
+
+Deno.test("(unstable) takeWhile() handles negatives", () => {
+  const arr = [-1, -2, -3, -4, -5, -6];
+
+  const actual = unstableTakeWhile(arr, (i) => i > -4);
+  assertEquals(actual, [-1, -2, -3]);
+});
+
+Deno.test("(unstable) takeWhile() handles no mutation", () => {
+  const arr = [-1, -2, -3, -4, -5, -6];
+
+  const actual = unstableTakeWhile(arr, (i) => i > -4);
+  assertEquals(actual, [-1, -2, -3]);
+  assertEquals(arr, [-1, -2, -3, -4, -5, -6]);
+});
+
+Deno.test("(unstable) takeWhile() handles empty input array returns empty array", () => {
+  const arr: number[] = [];
+
+  const actual = unstableTakeWhile(arr, (i) => i > 4);
+
+  assertEquals(actual, []);
+});
+
+Deno.test("(unstable) takeWhile() returns empty array when the first element doesn't match the predicate", () => {
+  const arr = [1, 2, 3, 4];
+
+  const actual = unstableTakeWhile(arr, (i) => i !== 1);
+
+  assertEquals(actual, []);
+});
+
+Deno.test("(unstable) takeWhile() returns the same array when all elements match the predicate", () => {
+  const arr = [1, 2, 3, 4];
+
+  const actual = unstableTakeWhile(arr, (i) => i !== 400);
+
+  assertEquals(actual, [1, 2, 3, 4]);
+});
+
 Deno.test("(unstable) takeWhile() handles a generator", () => {
   function* infiniteCount() {
     let count = 0;

collections/unstable_take_while.ts

@@ -5,6 +5,8 @@
  * Returns all elements in the given collection until the first element that
  * does not match the given predicate.
  *
+ * @experimental **UNSTABLE**: New API, yet to be vetted.
+ *
  * @typeParam T The type of the elements in the iterable.
  *
  * @param iterable The iterable to take elements from.