lesson1

nodeJS/Learning/01/index.js

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+//Javascript Tutorial
+
+// Means Comment
+
+/* hehhe
+wow this is fun
+i am dumb */
+
+// Hello I 
+// can 
+// do this now
+
+// variable (var): want to make a empty box called dog, but expecting sth in there later
+// Can later assign Lucy to this box. variable originally empty box name is dog, but then the variable value is Lucy
+
+var dog;
+dog = "Buddy";
+console.log(dog);
+// var is the old name, it is a bad practice
+
+//let: will change, e.g. box called cat but give it a different cat (value) every single time
+let cat;
+cat = "Tom";
+console.log(cat);
+cat = "John";
+console.log(cat);
+
+//const: constant, thing in box will never change
+const bird = "sparrow";
+console.log(bird);
+
+//Data types: type of things u put in variable, e.g. tell box to put in specific type of value
+
+//Primitives Data Types
+//String, Number, Boolean, Undefined, Null
+
+//String: anything in single or double quotation, can type anything, show direct thing in quotation
+const funnystring = "John Doe";
+console.log(funnystring);
+
+//String concatenation
+const name1 = "John";
+const name2 = "Doe";
+const fullName = `The full name is ${name1} ${name2}`;
+console.log (fullName);
+console.log ("The full name is" + name1 + " " + name2);
+
+//String Escape Character, \ escapes the quotation
+console.log ("Ronald said \"It'\s raining outside\"");
+
+//String indexing: the computer recognizes it as each number assigned: every single letter on the word will have a index
+const string = "javascript bob";
+console.log(string[0]); //j
+console.log(string[5]); 
+console.log(string[11]);
+
+
+// Number: just a number (both one with decimal or one without)
+let age = 20;
+console.log (age);
+age = age + 15;
+console.log (age)
+
+//NaN: not a number
+let result = "Hello"/2;
+console.log(result);
+
+//infinity
+let infinity = 1/0
+console.log(infinity)
+
+//Boolean: true or false statements, all comparisons, !==" "
+console.log (1>2);
+console.log (5<7);
+console.log ("tiffany" !== "Tiffany")
+
+let tiffany = "tiffany" 
+let haha = "Tiffany"
+tiffany = haha
+console.log (tiffany == haha)
+
+//Undefined: did not give x anything
+let x;
+console.log(x);
+
+//Null: telling them theres nothing in the code
+let y = null;
+console.log(y);