Iterables:

add a [Symbol.Iterable] to make the object iterable so that the object can use for of loop
the [Symbol.Iterable] is a function, it should return a object includesdone and value
Array.from method can return Array.from a arraylike object and iterable object
string can be used in array.from as well

5.5Iterables/t.js

@@ -0,0 +1,55 @@
+let range = {
+				from: 1,
+				to: 5
+}
+
+range[Symbol.iterator] = function(){
+
+	return {
+		current: this.from,
+		last: this.to,
+		
+		next(){
+			if(this.current <= this.last){
+				return {done: false, value: this.current++};
+			} else {
+				return {done: true};
+			}
+		}
+	}
+};
+
+
+for(let num of range){
+	console.log(num);
+}
+
+for(let ch of "tests"){
+	console.log(ch)
+}
+
+let arrayLike = {
+	0: "Hello",
+	1: "World",
+	length: 2
+};
+
+// Array.from
+let arr = Array.from(arrayLike);
+console.log(arr.pop()); // World
+arr = Array.from(range);
+console.log(arr); //1, 2, 3, 4, 5
+arr = Array.from(range, num => num * num);
+console.log(arr); //1, 4, 9, 16, 25
+
+let s = "split";
+let split_s = s.split('');
+let arr_s = Array.from(s);
+console.log(split_s);
+console.log(split_s[0]);
+console.log(split_s[1]);
+console.log(split_s.length);
+console.log(arr_s);
+console.log(arr_s[0]);
+console.log(arr_s[1]);
+console.log(arr_s.length);