Bump lodash from 4.17.15 to 4.17.19

package.json

@@ -0,0 +1,17 @@
+{
+  "name": "fp-practice",
+  "version": "1.0.0",
+  "description": "",
+  "main": "src/index.js",
+  "scripts": {
+    "start": "nodemon src/index.js localhost 8080"
+  },
+  "dependencies": {
+    "lodash": "4.17.19",
+    "ramda": "0.26.1"
+  },
+  "devDependencies": {
+    "nodemon": "1.18.4"
+  },
+  "keywords": []
+}

src/index.js

@@ -0,0 +1,54 @@
+const R = require("ramda");
+const { log } = console;
+const { compose, map, equals } = R;
+
+class Functor {
+  static of(value) {
+    return new Functor(value);
+  }
+  constructor(value) {
+    this.value = value;
+  }
+  fmap(f) {
+    return new Functor(f(this.value));
+  }
+}
+
+const gt0 = num => num > 0;
+const fNum10 = new Functor(10);
+const fNum10AfterGt = fNum10.fmap(gt0);
+const fNum10AfterGtR = R.map(gt0, fNum10);
+
+// Functor {value:10}
+// Functor {value: true}
+// {value:true}
+log(fNum10, fNum10AfterGt, fNum10AfterGtR);
+
+log(R.map(gt0, [10])); // [true]
+
+log(new Functor(10).fmap(gt0));
+
+//
+const id = x => x;
+const f = price => price * 1.05 + 10;
+const g = total => total + 100;
+const fg = compose(
+  g,
+  f
+);
+
+const f90 = Functor.of(90);
+// Identity
+log(equals(f90.fmap(id), Functor.of(id(90))));
+// Compose
+log(f90.fmap(f).fmap(g));
+log(f90.fmap(fg));
+log(
+  map(
+    compose(
+      g,
+      f
+    ),
+    f90
+  )
+);