In Client side we code in ?

LET'S FOCUS ON

In shorts

     used to create interactive websites

SOME FACTS

• Was written in 1997 over the span of 10 days by Brenden Eich

• Intends to take us a step beyond static HTML

• IT'S NOT JAVA
  • an implementation of ECMAScript SPEC
  • each browser implements the engine as it sees fit

• NO COMPILER​
  • oh what fun...

SO JAVASCRIPT

• lacks conformity between browsers
• has no compiler to help us
• full of "gotchas" that silently introduce bugs
• Is not java... yet most programmers code like it is...

EXAMPLES

DAMN BROwSER

(function() {

   var a = "initial";
   if(a) {
       function f() { console.log("1") };
   } else {
       function f() { console.log("2") };
   }
   f();

})()

What would be printed

1 ?

2 ?

MORE TO FEAR FROM

console.log(typeof greet);
greet();

var greet = function() {
   alert("hello!");
}

console.log(typeof greet);
greet();

function greet() {
   alert("hello!");
}

VS.

'USE STRICT' !!!!!!!!!!!!!

if(undefined = "foo") {
    ...
}

IE8

And So MANY MORE...

USE A "LINTER" :)

STATIC CODE ANALYSIS

"Lint" tools read your source code and look for common mistakes...

It will not make you a better coder ;)

(function() {
   var a = "initial";
   if(a) {
       function f() { console.log("1") };
   } else {
       function f() { console.log("2") };
   }
   f();
})()

LINT WILL GENERATE AN ERROR DURING BUILD

 "NO INNER FUNCTION DECLARATION" 

SO WHY ESLINT

• It's more flexible (~140 Rules, all can be turned off)
  • We are currently monitoring ~40
• It's blazing fast
• It's actively maintained and developed
• AND IT'S EXTENSIBLE
  • Soon - angularJS rules !

SHOW ME THE MONEY

FORMALITIES

• You can find our list of rules: *HERE*
• You can find HOWTO's: *HERE*

I am sending list of errors every Sunday to TL

Thank you