Rules

Rules in ESLint are divided into several categories to help you better understand their value. Additionally, not all rules are enabled by default. Those that are not enabled by default are marked as being off.

Possible Errors

The following rules point out areas where you might have made mistakes.

no-console - disallow use of console
no-debugger - disallow use of debugger
no-empty - disallow empty statements
no-unreachable - disallow unreachable statements after a return, throw, continue, or break statement
use-isnan - disallow comparisons with the value NaN

Best Practices

These are rules designed to prevent you from making mistakes. They either prescribe a better way of doing something or help you avoid footguns.

[no-caller] - disallow use of arguments.caller or arguments.callee are used
[curly] - require curly brace for all control statements
[eqeqeq] - require the use of === and !==
[no-eval] - disallow use of eval()
[no-with] - disallow use of the with statement
[no-undef-init] - disallow use of undefined when initializing variables
[no-floating-decimal] - disallow the use of leading or trailing decimal points in numeric literals
[no-octal] - disallow use of octal literals
[no-new] - disallow use of new operator when not part of the assignment or comparison

Stylistic Issues

These rules are purely matters of style and are quite subjective.

[camelcase] - require camel case names
new-cap - require a capital letter for constructors
quote-props - require quotes around object literal property names
[semi] - require use of semicolons instead of relying on ASI

Alternate Rules

smarter-eqeqeq - require the use of === and !== when it makes sense to use them

Legacy

The following rules are included for compatibility with JSHint and JSLint. While the names of the rules may not match up with the JSHint/JSLint counterpart, the functionality is the same.

[no-bitwise] - disallow use of bitwise operators (off by default)
[guard-for-in] - make sure for-in loops have an if statement (off by default)