Created chapter 02

chapter01/package.json

@@ -27,7 +27,9 @@
         },
         "extends": ["eslint:recommended", "plugin:flowtype/recommended"],
         "plugins": ["flowtype"],
-        "rules": {}
+        "rules": {
+            "no-console": "off"
+        }
     },
     "prettier": {
         "tabWidth": 4,

chapter02/package.json

@@ -0,0 +1,51 @@
+{
+    "name": "simpleproject",
+    "version": "1.0.0",
+    "description": "A simple project to show package.json creation",
+    "main": "index.js",
+    "scripts": {
+        "build": "babel src -d out",
+        "buildNode": "flow-remove-types src/ -d out/",
+        "flow": "flow",
+        "eslint": "eslint src",
+        "test": "echo \"Error: no test specified\" && exit 1"
+    },
+    "author": "Federico Kereki",
+    "license": "ISC",
+    "babel": {
+        "presets": ["env", "flow"]
+    },
+    "eslintConfig": {
+        "parserOptions": {
+            "ecmaVersion": 2017,
+            "sourceType": "module"
+        },
+        "parser": "babel-eslint",
+        "env": {
+            "browser": true,
+            "node": true
+        },
+        "extends": ["eslint:recommended", "plugin:flowtype/recommended"],
+        "plugins": ["flowtype"],
+        "rules": {
+            "no-console": "off"
+        }
+    },
+    "prettier": {
+        "tabWidth": 4,
+        "printWidth": 75
+    },
+    "dependencies": {},
+    "devDependencies": {
+        "babel-cli": "^6.26.0",
+        "babel-eslint": "^8.2.2",
+        "babel-preset-env": "^1.6.1",
+        "babel-preset-flow": "^6.23.0",
+        "eslint": "^4.19.0",
+        "eslint-config-recommended": "^2.0.0",
+        "eslint-plugin-flowtype": "^2.46.1",
+        "flow-bin": "^0.68.0",
+        "flow-remove-types": "^1.2.3",
+        "prettier": "^1.11.1"
+    }
+}

chapter02/src/extdate.js

@@ -0,0 +1,59 @@
+class ExtDate extends Date {
+    fullDate() {
+        const months = [
+            "JAN",
+            "FEB",
+            "MAR",
+            "APR",
+            "MAY",
+            "JUN",
+            "JUL",
+            "AUG",
+            "SEP",
+            "OCT",
+            "NOV",
+            "DEC"
+        ];
+
+        return (
+            months[this.getMonth()] + 
+            " " +
+            String(this.getDate()).padStart(2, "0") +
+            " " +
+            this.getFullYear()
+        );
+    }
+
+    static getMonthName(m) {
+        const months = [
+            "JAN",
+            "FEB",
+            "MAR",
+            "APR",
+            "MAY",
+            "JUN",
+            "JUL",
+            "AUG",
+            "SEP",
+            "OCT",
+            "NOV",
+            "DEC"
+        ];
+        return months[m];
+    }
+    
+    fullDate2() {
+        return (
+            ExtDate.getMonthName(this.getMonth()) +
+            " " +
+            String(this.getDate()).padStart(2, "0") +
+            " " +
+            this.getFullYear()
+        );
+    }
+}
+
+console.log(new ExtDate().fullDate()); // "MAY 01 2018"
+
+console.log(ExtDate.getMonthName(8));  // "SEP"
+console.log(new ExtDate().fullDate2()); // "MAY 01 2018"

chapter02/src/persons.js

@@ -0,0 +1,130 @@
+class Person {
+    constructor(first, last) {
+        this.first = first;
+        this.last = last;
+    }
+
+    initials() {
+        return `${this.first[0]}${this.last[0]}`;
+    }
+
+    fullName() {
+        return `${this.first} ${this.last}`;
+    }
+
+    get lastFirst() {
+        return `${this.last}, ${this.first}`;
+    }
+
+    set lastFirst(lf) {
+        // very unsafe; no checks!
+        const parts = lf.split(",");
+        this.last = parts[0];
+        this.first = parts[1];
+    }
+}
+
+pp = new Person("Erika", "Mustermann");
+console.log(pp); // Person {first: "Erika", last: "Mustermann"}
+console.log(pp.initials()); // "EM"
+console.log(pp.fullName()); // "Erika Mustermann"
+
+pp.lastFirst = "Svensson, Sven";
+console.log(pp); // Person {first: " Sven", last: "Svensson"}
+
+class Developer extends Person {
+    constructor(first, last, language) {
+        super(first, last);
+        this.language = language;
+    }
+
+    fullName() {
+        // redefines the original method
+        return `${super.fullName()}, ${this.language} dev`;
+    }
+}
+
+window.dd = new Developer("John", "Doe", "JS");
+console.log(dd); // Developer {first: "John", last: "Doe", language: "JS"}
+console.log(dd.initials()); // "JD"
+console.log(dd.fullName()); // "John Doe, JS dev"
+
+const toJsonMixin = base =>
+    class extends base {
+        toJson() {
+            return JSON.stringify(this);
+        }
+    };
+
+const countKeysMixin = base =>
+    class extends base {
+        countKeys() {
+            return Object.keys(this).length;
+        }
+    };
+
+    class PersonWithTwoMixins extends toJsonMixin(countKeysMixin(Person)) {
+        toJson() { 
+            // redefine the method, just for the sake of it
+             return "NEW TOJSON " + super.toJson();
+        }
+    }
+
+    
+    p2m = new PersonWithTwoMixins("Jane", "Roe");
+    console.log(p2m);
+    console.log(p2m.toJson());    // NEW TOJSON {"first":"Jane","last":"Roe"}
+    console.log(p2m.countKeys()); // 2
+
+
+
+    class ExtDate extends Date {
+        fullDate() {
+            const months = [
+                "JAN",
+                "FEB",
+                "MAR",
+                "APR",
+                "MAY",
+                "JUN",
+                "JUL",
+                "AUG",
+                "SEP",
+                "OCT",
+                "NOV",
+                "DEC"
+            ];
+    
+            return (
+                months[this.getMonth()] + 
+                " " +
+                String(this.getDate()).padStart(2, "0") +
+                " " +
+                this.getFullYear()
+            );
+        }
+    
+    
+        static getMonthName(m) {
+            const months = [
+                "JAN",
+                "FEB",
+                // etc...
+                "NOV",
+                "DEC"
+            ];
+            return months[m];
+        }
+    
+        fullDate2() {
+            return (
+                ExtDate.getMonthName(this.getMonth()) +
+                " " +
+                String(this.getDate()).padStart(2, "0") +
+                " " +
+                this.getFullYear()
+            );
+        }
+    }
+    
+    console.log(new ExtDate().fullDate()); // "MAY 01 2018"