JSLint

JMU

JSLint
A Static Analysis Tool for ECMAScript/JavaScript

Prof. David Bernstein
James Madison University

Computer Science Department

bernstdh@jmu.edu

Introduction

Purpose:
- Simple static analysis style checking and structure checking
Motivation:
- "Many of the features that were intended to make [JavaScript] easy to use are troublesome when projects become more complicated."

Some Details

Global Variables:
- Requires all variables and functions to be defined before they are used
Semicolons:
- Every statement except for, function, if, switch, try and while must be followed by a semicolon
Commas:
- Must be used only as a separator not an operator
- Must not use extra commas
Block Scope:
- Must not declare a variable in a block
Block Statements:
- Requires block statements in conditional statements and loop statements

Controlling JSLint

On-Line (www.jslint.com):
- Options are selected with checkboxes
Off-Line:
- Can be specified using the /*jslint */ directive (note that there is no space before the j)
- IDEs often allow you to filter the report

Not Surprisingly

The Controversy:
- Everyone doesn't agree with JSLint
A Fork:
- JSHint is a fork that allows for customization