Improve partial examples

Author: tshemsedinov

JavaScript/4-partial.js

@@ -11,3 +11,8 @@ const f12 = partial(f11, 2);
 const f13 = partial(f12, 3);
 const y1 = f13(4);
 console.log(y1);
+
+const f21 = partial(sum4, 1, 2);
+const f22 = partial(f21, 3);
+const y2 = f22(4);
+console.log(y2);

JavaScript/5-partial-ext.js

@@ -0,0 +1,18 @@
+'use strict';
+
+const partial = (fn, ...args) => (...rest) => fn(...args.concat(rest));
+
+// Usage
+
+const sum4 = (a, b, c, d) => (a + b + c + d);
+
+const f11 = partial(sum4, 1);
+const f12 = partial(f11, 2);
+const f13 = partial(f12, 3);
+const y1 = f13(4);
+console.log(y1);
+
+const f21 = partial(sum4, 1, 2);
+const f22 = partial(f21, 3);
+const y2 = f22(4);
+console.log(y2);