morning code demos

Author: ericwgreene

public/demos/array_creation.js

@@ -0,0 +1,19 @@
+
+// const nums = [ 1,2,3,4,5 ]; 
+
+// console.log(nums instanceof Array);
+// console.log(Array.isArray(nums));
+
+function doIt() {
+
+  //console.log(arguments instanceof Array);
+  //console.log([]);
+  //console.log(arguments);
+
+  const args = Array.from(arguments);
+
+  console.dir(args);
+
+}
+
+doIt(1,2,3,4,5);

public/demos/arrays_immutable.js

@@ -0,0 +1,14 @@
+
+
+const nums = [ 1, 2, 3, 4, 5 ];
+
+const newNums = nums.concat(9).slice(1, 4);
+
+console.log(nums);
+console.log(newNums);
+
+// console.log(nums.length);
+// console.log(newNums.length);
+
+// console.log(nums === newNums);
+

public/demos/arrays_mutable.js

@@ -0,0 +1,25 @@
+
+
+const nums = [ 1, 2, 3, 4, 5 ];
+
+console.log(nums);
+console.log(nums.length);
+
+// console.log(nums.push(9));
+// console.log(nums);
+// console.log(nums.unshift(-9));
+// console.log(nums);
+// console.log(nums.pop());
+// console.log(nums);
+// console.log(nums.shift());
+// console.log(nums);
+
+nums.splice(2, 1, 9);
+console.log(nums);
+
+// nums.sort();
+// console.log(nums);
+
+nums.reverse();
+console.log(nums);
+

public/demos/boolean.js

@@ -0,0 +1,20 @@
+
+// falsy
+
+// 0
+// ''
+// false
+// undefined
+// null
+// NaN
+
+// if ({}) {
+//   console.log('truthy');
+// } else {
+//   console.log('falsy');
+// }
+
+var t = 1 && 2;
+
+console.log(t);
+

public/demos/epsilon.js

@@ -0,0 +1,11 @@
+
+console.log(0.1 + 0.2);
+console.log(0.1 + 0.3);
+
+console.log(Number.EPSILON);
+
+// not this way
+console.log( (0.1 + 0.2) === 0.3);
+
+// (0.1 + 0.2) === 0.3
+console.log( Math.abs((0.1 + 0.2) - 0.3) < Number.EPSILON );

public/demos/functions.js

@@ -0,0 +1,17 @@
+
+const doIt = function (a,b,c,...d) {
+
+  console.log(a,b,c,d);
+
+  return a + b;
+
+};
+
+// const fn = doIt;
+
+// fn();
+
+const result = doIt(1,2,3,4,5,6);
+console.log(result);
+
+

public/demos/number.js

@@ -0,0 +1,18 @@
+
+// console.log(0.1 + 0.2);
+
+// console.log(Number.MAX_SAFE_INTEGER);
+// console.log(Number.MAX_SAFE_INTEGER + 1);
+// console.log(Number.MAX_SAFE_INTEGER + 2);
+
+// console.log(Infinity);
+// console.log(-Infinity);
+// console.log(Infinity + Infinity);
+// console.log(Infinity * Infinity);
+// console.log(Infinity / Infinity);
+
+var t = parseInt('Hello!');
+
+console.log(isNaN(t));
+
+console.log(typeof NaN);

public/demos/string.js

@@ -0,0 +1,20 @@
+
+var fn = 'Eric';
+var age = 40;
+
+var message = `${fn} 
+  is ${age} 
+  years
+  old.`;
+
+console.log(message);
+
+console.log(message.length);
+
+var test = 'qazwsxedc';
+
+console.log(test.slice(3, 6));
+
+test.substr()
+
+console.log('Eric' + ' ' + 'Greene');

public/demos/types.js

@@ -0,0 +1,39 @@
+
+var t;
+
+console.log(typeof t);
+
+t= 0;
+console.log(typeof t);
+
+t = 'Hello World!';
+console.log(typeof t);
+
+t = true;
+console.log(typeof t);
+
+t = Symbol('demo');
+console.log(typeof t);
+
+t = null;
+console.log(typeof t);
+
+t = {
+  firstName: 'Bob',
+  lastName: 'Smith',
+};
+console.log(typeof t);
+
+t = [1,2,3,4,5];
+console.log(typeof t);
+
+t = function() { };
+console.log(typeof t);
+
+t = class {};
+console.log(typeof t);
+
+
+
+
+

public/index.html

@@ -10,4 +10,34 @@ <h1>Welcome to Introduction to ES2017 for React + GraphQL Developers!</h1>
 
 <script src="js/bundle.js"></script>
 
+<script>
+
+  'use strict';
+
+  function outer() {
+
+    console.log(this);
+
+
+    const inner = () => {
+      console.log(this);
+    };
+
+    inner();
+  }
+
+  // outer();
+  // window.outer();
+
+  const o = {
+    id: 2,
+    outer: outer,
+  };
+
+  o.outer();
+
+  // console.log(outer === o.outer);
+
+</script>
+