Monday, July 14, 2014

Introduction to JavaScript pt. I

The following are the most basic and quick/important things about JavaScript (JS):

"A method method is used to define new methods."

// exclusively for commenting You can get syntax errors using /* */

Names can be anything that is a letter followed by more letters, #'s, or underbars-- EXCEPT for the following reserved words which will tell the program to do a certain task (these should be familiar if you have done any other programming) such as abstract, long, return, etc…

Numbers in JS have only one type and is 64 (wholeee) bits as a floating type. To explain how it is all one type.. in JS, 10 and 10.0 are equivalent. This eliminates the need to know what type of number to call when you are programming. You can use exponents by placing an e, so 1e2 would represent 100.

NaN is not equal to any value, even itself (to me this is an entertaining idea). JS ises the function below to determine if something has a value or not: isNaN(number)

If you use infinity as a value it will go to about 1.8e+308 -- I think that's quite infinite. That’s a lot of moles of Avogadro's numbers of molecules etc..

I had a chemistry professor one day who said if we brought him Avogadro's constant in pennies he would give us an A. Avogadro's number in chemistry is: 6.0221413e+23 :D think about that for a second!

The following method will convert any number --> integer:

Strings have characters inside them and backslash is an escape character. There is no character function, so just put one character into a string-- same ideas as the number system mentioned above. Strings have a length property that counts the number of characters in it. For example, "one".length would give you 3, because there are three letters in the word "one."

You can concatenate strings together as the following are equivalent:

There are many types of statements to "do stuff" with JS, and logically, it goes top to bottom.

  • conditional statements (if/then and switch)
  • looping statements (while, for, and do)
  • disruptive statements (break, return, and throw)

Literals can specify new objects and their properties will either be a name or string. Because literals are not considered a variable, the property name has to be known when compiling.

Source: Crockford, Douglas. "JavaScript: The Good Parts." O'Reilly Media / Yahoo Press. (2008).