feat(loopDoWhile)

src/loop-do-while/__snapshots__/loop-do-while.spec.ts.snap

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

src/loop-do-while/index.ts

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

src/loop-do-while/loop-do-while.spec.ts

@@ -0,0 +1,21 @@
+import { loopDoWhile } from './loop-do-while';
+
+describe('loopDoWhile function', () => {
+  const input = [1, 2, 3, 4, 5];
+
+  test('is a pure function', () => {
+    loopDoWhile<ReadonlyArray<number>>(
+      arr => arr.length < 10,
+      arr => [...arr, 0]
+    )(input);
+    expect(input).toMatchSnapshot();
+  });
+
+  test('2 |> loopDoWhile <10,  x => x² === 16', () => {
+    expect(loopDoWhile<number>(x => x < 10, x => x ** 2)(2)).toBe(16);
+  });
+
+  test('2 |> loopDoWhile <10,  x => x² === 16', () => {
+    expect(loopDoWhile<number>(x => x < 10, x => x ** 2)(10)).toBe(100);
+  });
+});

src/loop-do-while/loop-do-while.ts

@@ -0,0 +1,36 @@
+/**
+ * @module TBD_A=>TBD_B
+ */
+/**
+ * This method loop on an input:
+ * - at first, output = iteratee(input)
+ * - while predicat(output) is true, output = iteratee(output)
+ * - finally, returns output
+ * @param predicate The function apply on each loop to decide to :
+ * continue (return true), or to stop (return false)
+ * @param iteratee The iteratee invoked on each loop.
+ * @return the function to apply on the input
+ * @example
+ * ```
+ * loopDoWhile<number>(x => x < 10, x => x ** 2)(10) // 100
+ * ```
+ * @example Using the chain
+ * ```
+ * chain(10)
+ *   .chain(loopDoWhile<number>(x => x < 10, x => x ** 2))
+ *   .value() // 100
+ * ```
+ */
+export function loopDoWhile<T>(
+  predicate: (element: T) => boolean,
+  iteratee: (element: T) => T
+): (input: T) => T {
+  return (input: T) => {
+    let output = input;
+    do {
+      output = iteratee(output);
+    } while (predicate(output));
+
+    return output;
+  };
+}

src/taninsam.ts

@@ -25,6 +25,7 @@ export * from './join';
 export * from './keys';
 export * from './last';
 export * from './length';
+export * from './loop-do-while';
 export * from './loop-for';
 export * from './map';
 export * from './max';