Create solution 1-pipe in TypeScript

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));
+