Introducing Closure Linter

When collaborating with lots of engineers as we do here at Google, it’s important to keep a consistent coding style. To this end, we recently open sourced the Google JavaScript Style Guide.

Today we’re happy to announce we’re open sourcing a tool that will help you follow that style guide with minimal manual effort - the Closure Linter.

Take for example, this code:

var x = 10
var y=20;

for(var i = 0;i < 10; i++ ) {
  x += i;
   y -= i;
}

var z = [10, 20,];

x = y + z[0]
    + 10;

When we run gjslint --strict fixme.js we get

Line 1, E:0010: (New error) Missing semicolon at end of line
Line 2, E:0002: Missing space before "="
Line 2, E:0002: Missing space after "="
Line 4, E:0002: Missing space before "("
Line 4, E:0002: Missing space after ";" in for statement
Line 4, E:0001: Extra space before ")"
Line 6, E:0006: (New error) Wrong indentation: expected any of {2} but got 3
Line 9, E:0121: Illegal comma at end of array literal
Line 12, E:0120: Binary operator should go on previous line "+"
Found 9 errors, including 2 new errors, in 1 files (0 files OK).

Even better, if we run fixjsstyle --strict fixme.js, 7 of the 9 errors are automatically fixed for us!

We hope you can use the Closure Linter to improve your style consistency while simultaneously saving time. More information on how to get started can be found on the How to Use Closure Linter page.

We welcome comments and questions in the discussion forum.

Posted by Robby Walker and Andy Perelson, Software Engineers