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

5.4ArrayMethod/t.js

@@ -49,3 +49,53 @@ console.log(`arr.sort(): ${arr.sort((a,b) => a - b)}`);
 
 let countries = ['Österreich', 'Andorra', 'Vietnam'];
 console.log(countries.sort((a,b) => a.localeCompare(b)))
+
+// arr.reverse()
+countries = countries.reverse()
+console.log(countries)
+
+// arr.split() and arr.join()
+let names = "Bilbo, Gandalf, Nazgul";
+
+let nameLists = names.split(', ');
+
+for(let name of nameLists){
+    console.log(`A message to ${name}`);
+}
+// [LOG - 6/16/24 21:32:14] "A message to Bilbo"
+// [LOG - 6/16/24 21:32:14] "A message to Gandalf"
+// [LOG - 6/16/24 21:32:14] "A message to Nazgul"
+
+nameLists = names.split(', ', 2);
+for(let name of nameLists){
+    console.log(`A message to ${name}`);
+}
+// [LOG - 6/16/24 21:32:14] "A message to Bilbo"
+// [LOG - 6/16/24 21:32:14] "A message to Gandalf"
+
+console.log(`nameLists: ${nameLists.join('; ')}`)
+// [LOG - 6/16/24 21:33:45] "nameLists: Bilbo; Gandalf"
+
+
+// arr.reduce(fn) arr.reduceRight(fn)
+let numbers = [1,2,3,4,5]
+console.log(numbers.reduce(function(sum, current){
+    return sum + current;
+}, 0));
+console.log(numbers.reduce((sum, cur) => sum + cur, 0));
+console.log(numbers.reduceRight((sum, cur) => sum + cur, 0));
+
+// Array.isArray()
+console.log(Array.isArray(countries))
+
+function camelize(str){
+    words = str.split('-')
+    for(let i = 1; i < words.length; i++){
+        words[i][0] = words[i][0].toUpperCase();
+        console.log(words[i])
+    }
+    return words.join('');
+}
+console.log(camelize("background-color"))
+console.log(camelize("list-style-image"))
+console.log(camelize("-webkit-translation"))

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);