feat(loopUntil)

src/loop-until/__snapshots__/loop-until.spec.ts.snap

@@ -0,0 +1,11 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`loopUntil function is a pure function 1`] = `
+Array [
+  1,
+  2,
+  3,
+  4,
+  5,
+]
+`;

src/loop-until/index.ts

@@ -0,0 +1 @@
+export * from './loop-until';

src/loop-until/loop-until.spec.ts

@@ -0,0 +1,17 @@
+import { loopUntil } from './loop-until';
+
+describe('loopUntil function', () => {
+  const input = [1, 2, 3, 4, 5];
+
+  test('is a pure function', () => {
+    loopUntil<ReadonlyArray<number>>(
+      arr => 10 < arr.length,
+      arr => [...arr, 0]
+    )(input);
+    expect(input).toMatchSnapshot();
+  });
+
+  test('2 |> loopUntil 10<,  x => x² === 16', () => {
+    expect(loopUntil<number>(x => 10 < x, x => x ** 2)(2)).toBe(16);
+  });
+});

src/loop-until/loop-until.ts

@@ -0,0 +1,36 @@
+/**
+ * @module any=>any
+ */
+/**
+ * This method loop on an input:
+ * - at first, output = input
+ * - while predicat(output) is false, output = iteratee(output)
+ * - finally, returns output
+ * @param predicate The function apply on each loop to decide to :
+ * continue (return false), or to stop (return true)
+ * @param iteratee The iteratee invoked on each loop.
+ * @return the function to apply on the input
+ * @example
+ * ```
+ * loopWhile<number>(x => 10 < x, x => x ** 2)(2) // 16
+ * ```
+ * @example Using the chain
+ * ```
+ * chain(2)
+ *   .chain(loopWhile<number>(x => 10 < x, x => x ** 2))
+ *   .value() // 16
+ * ```
+ */
+export function loopUntil<T>(
+  predicate: (element: T) => boolean,
+  iteratee: (element: T) => T
+): (input: T) => T {
+  return (input: T) => {
+    let output = input;
+    while (!predicate(output)) {
+      output = iteratee(output);
+    }
+
+    return output;
+  };
+}

src/taninsam.ts

@@ -26,6 +26,7 @@ export * from './keys';
 export * from './last';
 export * from './length';
 export * from './loop-for';
+export * from './loop-until';
 export * from './map';
 export * from './max';
 export * from './max-by';