Add object reflection: omap

Author: tshemsedinov

JavaScript/5-instance.js

@@ -4,9 +4,12 @@
 
 // Imperative
 
-const marcus = {
+const marcus1 = {
   name: 'Marcus Aurelius',
   born: 121,
+  upperName() {
+    this.name = this.name.toUpperCase();
+  },
   get era() {
     return this.born < 0 ? 'BC' : 'AD';
   },
@@ -15,13 +18,41 @@ const marcus = {
   },
 };
 
-console.log(`${marcus}`);
+marcus1.name += ' Antoninus';
+marcus1.city = 'Roma';
+marcus1.position = 'emperor';
+marcus1.upperName();
+console.log(`Era of ${marcus1.name} birth is ${marcus1.era}`);
+console.log(`${marcus1}`);
+const keys = Object.keys(marcus1);
+console.log('Fields:', keys.join(', '));
 
 // Functional
 
 const era = year => (year < 0 ? 'BC' : 'AD');
 const person = (name, born) => () => `${name} was born in ${born} ${era(born)}`;
 
 const marcus2 = person('Marcus Aurelius', 121, 'Roma');
-
 console.log(marcus2());
+
+// Object reflection
+
+const omap = (obj, fn) => Object.keys(obj)
+  .reduce((res, key) => {
+    const [prop, val] = fn(key, obj[key]);
+    res[prop] = val;
+    return res;
+  }, {});
+
+const marcus3 = {
+  firstName: 'Marcus',
+  middleName: 'Aurelius',
+  lastName: 'Antoninus',
+};
+
+const marcus4 = omap(marcus3, (key, val) => {
+  const prop = key.toLowerCase().replace('name', '');
+  const value = val.toUpperCase();
+  return [prop, value];
+});
+console.log(marcus4);