From 052e591e21b719482431c833fdeef619b0642057 Mon Sep 17 00:00:00 2001
From: D_MENT <44676701+rocket111185@users.noreply.github.com>
Date: Thu, 25 Mar 2021 12:44:44 +0200
Subject: [PATCH] Create solution 1-pipe in TypeScript

The example shows that TypeScript allows you to define the contract so you don't have to check the types implicitly.
---
 Solutions/1-pipe.ts | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)
 create mode 100644 Solutions/1-pipe.ts

diff --git a/Solutions/1-pipe.ts b/Solutions/1-pipe.ts
new file mode 100644
index 0000000..d4b0fee
--- /dev/null
+++ b/Solutions/1-pipe.ts
@@ -0,0 +1,33 @@
+'use strict';
+
+// Define the type "function, that takes one argument
+// and returnes the value of the same type"
+type oneArg<T> = (arg: T) => T;
+
+// Construct the "pipe" so it suits the exercise requirements
+const pipe = <T>(...fns: oneArg<T>[]): oneArg<T> =>
+  x => fns.reduce((v, f) => f(v), x);
+
+
+// Usage
+
+const inc = (x: number) => ++x;
+const twice = (x: number) => x * 2;
+const cube = (x: number) => Math.pow(x, 3);
+
+// You cannot do:
+//
+// const wrongFunc = x => 'someString';
+// pipe(inc, twice, wrongFunc);
+
+// Also you cannot do:
+//
+// const wrongFunc = (x, y) => x + y;
+// pipe(inc, twice, wrongFunc);
+
+// Because wrongFunc does not suit the type
+// (arg: T) => T
+
+const f = pipe(inc, twice, cube);
+console.log(f(5));
+