eslint-config-jhh/rules/best-practices.js

JHH ESLint config

/**
 * These rules relate to better ways of doing things to help you avoid problems
 *
 * @see http://eslint.org/docs/rules/#best-practices
 */

module.exports = {
    rules: {
        // enforce getter and setter pairs in objects
        'accessor-pairs': 'off',

        // enforce return statements in callbacks of array methods
        'array-callback-return': 'error',

        // enforce the use of variables within the scope they are defined
        'block-scoped-var': 'error',

        // enforce that class methods utilize this
        // Setting to warning to be have similar to IDEs such as Pycharm. This
        // way the user will be alerted that they can make the method static
        // and ignore the warning if they wish.
        'class-methods-use-this': ['warn', {
            exceptMethods: []
        }],

        // require return statements to either always or never specify values
        'consistent-return': 'error',

        // enforce consistent brace style for all control statements
        curly: ['error', 'multi-line'],

        // require default cases in switch statements
        // If you are skipping the default case intentionally you can avoid an
        // error by adding `// no default` at the end of the statement.
        'default-case': ['error', { commentPattern: '^no default$' }],

        // enforce consistent newlines before and after dots
        // Requires dot in a member expression should be on the same line as the
        // property portion.
        'dot-location': ['error', 'property'],

        // enforce dot notation whenever possible
        'dot-notation': ['error', { allowKeywords: true }],

        // require the use of === and !==
        eqeqeq: ['error', 'always', { null: 'ignore' }],

        // require for-in loops to include an if statement
        'guard-for-in': 'error',

        // disallow the use of alert, confirm, and prompt
        'no-alert': 'warn',

        // disallow use of arguments.caller or arguments.callee
        'no-caller': 'error',

        // disallow lexical declarations in case clauses
        'no-case-declarations': 'error',

        // disallow else blocks after return statements in if statements
        'no-else-return': 'error',

        // disallow empty functions
        'no-empty-function': ['error'],

        // disallow empty destructuring patterns
        'no-empty-pattern': 'error',

        // disallow use of eval()
        // Die in a raging fire.
        'no-eval': 'error',

        // disallow extending native types
        // Hands off the natives pervert.
        'no-extend-native': 'error',

        // disallow unnecessary calls to .bind()
        'no-extra-bind': 'error',

        // disallow unnecessary labels
        'no-extra-label': 'error',

        // disallow fallthrough of case statements
        'no-fallthrough': 'error',

        // disallow leading or trailing decimal points in numeric literals
        'no-floating-decimal': 'error',

        // disallow assignments to native objects or read-only global variables
        'no-global-assign': 'error',

        // disallow shorthand type conversions
        'no-implicit-coercion': ['off', {
            boolean: false,  // !!foo is ok
            number: true,    // +foo is not ok
            string: true     // '' + foo is not ok
        }],

        // disallow variable and function declarations in the global scope
        'no-implicit-globals': 'error',

        // disallow the use of eval()-like methods
        'no-implied-eval': 'error',

        // disallow the use of the __iterator__ propert
        'no-iterator': 'error',

        // disallow labeled statements
        // I've never seen anyone here use a labeled statement so let's just
        // avoid that whole can of worms and forbid them.
        'no-labels': 'error',

        // disallow unnecessary nested blocks
        'no-lone-blocks': 'error',

        // disallow function declarations and expressions inside loop statements
        'no-loop-func': 'error',

        // disallow multiple spaces
        'no-multi-spaces': 'error',

        // disallow multiline strings
        'no-multi-str': 'error',

        // disallow new operators with the Function object
        'no-new-func': 'error',

        // disallow new operators with the String, Number, and Boolean objects
        'no-new-wrappers': 'error',

        // disallow octal escape sequences in string literals
        'no-octal-escape': 'error',

        // disallow octal literals
        'no-octal': 'error',

        // disallow octal escape sequences in string literals
        'no-octal-escape': 'error',

        // disallow reassigning function parameters
        'no-param-reassign': ['error', {
            props: true  // making allowance for React component props
        }],

        // disallow the use of the __proto__ property
        // WHAT YEAR IS THIS?!
        'no-proto': 'error',

        // disallow variable redeclaration
        'no-redeclare': 'error',

        // disallow assignment operators in return statements
        'no-return-assign': 'error',

        // disallow unnecessary return await
        'no-return-await': 'error',

        // disallow javascript: urls
        'no-script-url': 'error',

        // disallow assignments where both sides are exactly the same
        'no-self-assign': 'error',

        // disallow comparisons where both sides are exactly the same
        'no-self-compare': 'error',

        // disallow comma operators
        'no-sequences': 'error',

        // disallow throwing literals as exceptions
        'no-throw-literal': 'error',

        // disallow unused expressions
        'no-unused-expressions': ['error', {
            allowShortCircuit: true,  // a && b()
            allowTernary: true        // a ? b() : c()
        }],

        // disallow unused labels
        'no-unused-labels': 'error',

        // disallow unnecessary calls to .call() and .apply()
        'no-useless-call': 'error',

        // disallow unnecessary concatenation of literals or template literals
        'no-useless-concat': 'error',

        // disallow unnecessary escape characters
        'no-useless-escape': 'error',

        'no-useless-return': 'error',

        // disallow void operators
        'no-void': 'error',

        // disallow specified warning terms in comments
        // Warn if it spots a `todo` or `fixme` to remind you to actually do it
        'no-warning-comments': ['warn', {
            terms: ['todo', '@todo', 'fixme', '@fixme'],
            location: 'start'
        }],

        // disallow with statements
        'no-with': 'error',

        // enforce the consistent use of the radix argument when using
        // parseInt()
        radix: 'error',

        // require var declarations be placed at the top of their containing
        // scope
        'vars-on-top': 'error',

        // require parentheses around immediate function invocations
        'wrap-iife': ['error', 'outside'],

        // require or disallow “Yoda” conditions
        yoda: 'error'
    }
}