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JavaScript rules

The Codiga Static Analysis engine checks JavaScript code and supports many popular libraries. If you are using React, NextJS, Vue or Angular: the engine will flag any issue in your codebase. Automate your code reviews with Codiga and merge with confidence.

@typescript-eslint/ban-ts-comment

Best practice
Error

Detect any '@ts-<directive>' comment as it can reduce the effectiveness of TypeScript overall.

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@typescript-eslint/ban-types

Best practice
Error

Bans specific types and can suggest alternatives (such as String).

@typescript-eslint/explicit-function-return-type

Best practice
Error

Ensure that the values returned from functions are of the expected type

@typescript-eslint/explicit-module-boundary-types

Safety
Error

Ensure that the values returned from a module are of the expected type

@typescript-eslint/naming-convention

Code style
Error

Enforces naming conventions for everything across a codebase, in the settings verify if the naming-convention is camelCase, snake_case, etc.

@typescript-eslint/no-empty-function

Best practice
Error

Detect any empty methods, as in methods that do not have any logic

@typescript-eslint/no-unsafe-assignment

Safety
Error

Disallows assigning any to variables and properties as it creates a potential safety hole, and source of bugs in your codebase.

@typescript-eslint/no-unsafe-call

Safety
Error

Disallows calling an any type value as it creates a potential safety hole, and source of bugs in your codebase.

@typescript-eslint/no-unsafe-member-access

Safety
Error

Disallows member access on any typed variables as it creates a potential safety hole, and source of bugs in your codebase.

@typescript-eslint/no-unused-expressions

Best practice
Error

Disallow unused expressions. An unused expression which has no effect on the state of the program indicates a logic error.

@typescript-eslint/no-unused-vars

Best practice
Error

Disallow unused variables. Variables that are declared and not used anywhere in the code are most likely an error due to incomplete refactoring

@typescript-eslint/no-var-requires

Best practice
Error

Disallows the use of require statements except in import statements

@typescript-eslint/unbound-method

Safety
Error

Warns when a method is used outside of a method call.

compat/compat

Best practice
Error

This rule enables linting your code for browser compatibility.

constructor-super

Best practice
Error

Constructors of derived classes must call super()

eslint-comments/no-unused-disable

Best practice
Error

Disallow unused eslint-disable comments. Make sure all your rules are defined and are used correctly.

flowtype/no-weak-types

Safety
Error

Warns against weak type annotations any, Object and Function.

for-direction

Error prone
Error

Enforce "for" loop update clause moving the counter in the right direction.

getter-return

Error prone
Error

Enforces that a return statement is present in property getters

import/unambiguous

Security
Error

Warn if a module could be mistakenly parsed as a script by a consumer leveraging Unambiguous JavaScript Grammar to determine correct parsing goal.

jsx-a11y/click-events-have-key-events

Best practice
Error

Enforce onClick is accompanied by at least one of the following: onKeyUp, onKeyDown, onKeyPress

jsx-a11y/no-static-element-interactions

Best practice
Error

Disallow interactions in static elements. Static HTML elements do not have semantic meaning.

key-spacing

Code style
Error

Enforce consistent spacing between keys and values in object literal properties

max-statements

Best practice
Error

Check max number of statements for a function

mocha/prefer-arrow-callback

Unknown
Error

Definition for rule 'mocha/prefer-arrow-callback' was not found.

no-class-assign

Code style
Error

RegistrationForm' is a class.

no-compare-neg-zero

Error prone
Error

Detect the use of operator (e.g <=, <, ===, etc) to compare against -0.

no-const-assign

Code style
Error

Disallows assigning values to const as they're immutable.

no-control-regex

Error prone
Error

Control characters are special, invisible characters in the ASCII range 0-31. These characters are rarely used in JavaScript strings so a regular expression containing these characters is most likely a mistake.

no-dupe-class-members

Code style
Error

Disallow duplicate name in class members

no-dupe-else-if

Error prone
Error

Disallow duplicate conditions in if-else-if chains

no-dupe-keys

Error prone
Error

Disallow duplicate keys in object literals

no-duplicate-case

Error prone
Error

If a switch statement has duplicate test expressions in case clauses, it is likely that a programmer copied a case clause but forgot to change the test expression.

no-empty-pattern

Best practice
Error

Disallow empty destructuring patterns

no-func-assign

Error prone
Error

Disallow reassigning function declarations

no-global-assign

Best practice
Error

Disallow assignment to native objects or read-only global variables

no-inner-declarations

Error prone
Error

Disallow variable or function declarations in nested blocks

no-irregular-whitespace

Error prone
Error

Irregular whitespace not allowed.

no-misleading-character-class

Error prone
Error

Disallow characters which are made with multiple code points in character class syntax

no-prototype-builtins

Error prone
Error

Disallow use of Object.prototypes builtins directly

no-redeclare

Best practice
Error

Disallow variable redeclaration

no-regex-spaces

Error prone
Error

Disallow multiple spaces in regular expression literals

no-self-assign

Best practice
Error

Detects self assignments as they have no effect, so probably those are an error due to incomplete refactoring.

no-setter-return

Error prone
Error

Setter cannot return a value.

no-shadow-restricted-names

Code style
Error

Disallow shadowing of restricted names

no-unexpected-multiline

Error prone
Error

Disallow confusing multiline expressions

no-unreachable

Error prone
Error

Disallow unreachable code after return, throw, continue, and break statements

no-unsafe-finally

Error prone
Error

Disallow control flow statements in finally blocks

no-unsafe-negation

Error prone
Error

Disallow negating the left operand of relational operators

no-unused-labels

Best practice
Error

Disallow unused labels. Labels that are declared and not used anywhere in the code are most likely an error due to incomplete refactoring.

no-unused-vars

Code style
Error

Disallow unused variables. Variables that are declared and not used anywhere in the code are most likely an error due to incomplete refactoring

no-useless-catch

Best practice
Error

Disallow unnecessary catch clauses

no-useless-escape

Best practice
Error

Reports unnecessary escapes, as escaping non-special characters in strings, template literals, and regular expressions doesn't have any effect.

node/no-deprecated-api

Best practice
Error

Disallow deprecated APIs

node/no-missing-require

Error prone
Error

Disallow require() expressions which import non-existence modules

promise/catch-or-return

Safety
Error

Ensure that each time a then() is applied to a promise, a catch() is applied as well. Exceptions are made if you are returning that promise.

promise/prefer-await-to-then

Performance
Error

Use async/await style for managing concurrency instead of .then()

react-hooks/rules-of-hooks

Best practice
Error

React: Detects when rules of hooks are not being followed

react-internal/no-production-logging

Unknown
Error

React: Disallow internal logging when running in production

react-native/no-color-literals

Best practice
Error

React: Disallow color literals in styles

react-native/no-inline-styles

Unknown
Error

React: Styles should be defined in css blocks and not as inline of the web component or element

react/destructuring-assignment

Best practice
Error

React: Enforce consistent usage of destructuring assignment of props, state, and context

react/display-name

Best practice
Error

Prevent missing displayName in a React component definition

react/forbid-prop-types

Best practice
Error

React: By default this rule prevents vague prop types with more specific alternatives available (any, array, object), but any prop type can be disabled if desired.

react/jsx-key

Error prone
Error

React: Warn if an element that likely requires a key prop--namely, one present in an array literal or an arrow function expression.

react/jsx-no-duplicate-props

Error prone
Error

React: No duplicate props allowed

react/jsx-no-target-blank

Best practice
Error

React: This rules requires that you accompany target='\_blank' attributes with rel='noreferrer'.

react/jsx-no-undef

Error prone
Error

React: Detects potential ReferenceErrors resulting from misspellings or missing components.

react/no-array-index-key

Unknown
Error

React: Prevent usage of Array index in keys

react/no-children-prop

Best practice
Error

React: Prevent passing of children as props. Children should always be actual children, not passed in as a prop.

react/no-danger

Unknown
Error

React: Prevent usage of dangerous JSX properties

react/no-deprecated

Best practice
Error

React: Prevent usage of deprecated methods

react/no-direct-mutation-state

Error prone
Error

React: NEVER mutate this.state directly, as calling setState() afterwards may replace the mutation you made. Treat this.state as if it were immutable.

react/no-find-dom-node

Best practice
Error

React: Prevent usage of findDOMNode. Facebook will eventually deprecate findDOMNode as it blocks certain improvements in React in the future.

react/no-render-return-value

Best practice
Error

React: Prevent usage of the return value of ReactDOM.render

react/no-string-refs

Best practice
Error

React: Prevent using string references

react/no-unescaped-entities

Error prone
Error

React: Prevent invalid characters from appearing in markup

react/no-unknown-property

Error prone
Error

React: Prevent usage of unknown DOM property

react/prop-types

Best practice
Error

React: Prevent missing props validation in a React component definition

react/require-default-props

Best practice
Error

React: Enforce a defaultProps definition for every prop that is not a required prop

react/require-render-return

Best practice
Error

React: Enforce ES5 or ES6 class for returning value in render function

react/sort-comp

Best practice
Error

React: Enforce component methods order

react/style-prop-object

Best practice
Error

React: Enforce style prop value being an object

require-yield

Code style
Error

Disallow generator functions that do not have yield

security/detect-non-literal-regexp

Security
Error

Detects RegExp(variable), which might allow an attacker to DOS your server with a long-running regular expression.

sonarjs/no-identical-functions

Best practice
Error

When two functions have the same implementation, either it was a mistake - something else was intended - or the duplication was intentional, but may be confusing to maintainers.

standard/no-callback-literal

Best practice
Error

When invoking a callback function which uses the Node.js error-first callback pattern, all of your errors should either use the Error class or a subclass of it. It is also acceptable to use undefined or null if there is no error.

unicorn/consistent-destructuring

Best practice
Error

Use destructured variables over properties

unicorn/prefer-exponentiation-operator

Best practice
Error

Disallow the use of Math.pow in favor of the ** operator

valid-typeof

Error prone
Error

Enforce comparing typeof expressions against valid strings

vue/no-reserved-keys

Best practice
Error

Vue: Disallow overwriting reserved keys in Vue

vue/no-side-effects-in-computed-properties

Best practice
Error

Vue: Disallow side effects in computed properties

xo/throw-new-error

Best practice
Error

Use the new keyword when throwing an error