.eslintrc.js

/*
 * ESLint config for gsa js code
 *
 * - Syntax rules should be errors
 * - Coding style should be warnings
 */

module.exports = {
    extends: ['react-app'],
    settings: {
        react: {
            version: '16',
        },
    },
    rules: {
        'accessor-pairs': 'error', // require get xyz if set xyz is defined
        'block-scoped-var': 'error', // require var usage and definition at the same block
        'callback-return': 'error',
        camelcase: 'off', // don't require camelCase for functions and properties
        'class-methods-use-this': 'off', // don't enforce that class methods always utilize this
        'consistent-this': 'off',
        curly: 'error', // always require braces if (a) foo() is not allowed
        'dot-notation': [
            // require dot notation for object: abc.def instead of abc['def']
            'warn',
            {
                allowKeywords: true,
            },
        ],
        'func-names': [
            // disallow named function expressions
            'warn',
            'never',
        ],
        'func-style': [
            // enforce function expression instead of declaration
            'warn',
            'declaration',
            {
                allowArrowFunctions: true, // allow arrow functions
            },
        ],
        'global-require': 'warn', // enforce using require() on the top-level module scope
        'guard-for-in': 'off', // don't require hasOwnProperty call in for-in loops
        'handle-callback-err': 'error', // enforce callback error handling if callback has an error parameter
        indent: 'off',
        'init-declarations': 'off',
        'linebreak-style': [
            // require unix line endings (only \n)
            'error',
            'unix',
        ],
        'max-depth': [
            // enforce a maximum depth of 4 that blocks can be nested
            'warn',
            4,
        ],
        'max-lines': [
            'warn',
            {
                max: 5000,
                skipBlankLines: true,
            },
        ],
        'max-nested-callbacks': 'error',
        'max-params': [
            // allow only max 6 params
            'warn',
            6,
        ],
        'max-statements': 'off',
        'max-statements-per-line': [
            'warn',
            {
                max: 2,
            },
        ],
        'multiline-ternary': 'off',
        'newline-after-var': 'off',
        'newline-before-return': 'off',
        'no-alert': 'error',
        'no-bitwise': [
            // disallow bitwise operators. most of the time it's a typo for && and ||
            'warn',
            {
                allow: ['~', '<<', '>>'],
            },
        ],
        'no-catch-shadow': 'error',
        'no-console': 'warn',
        'no-div-regex': 'error',
        'no-duplicate-imports': 'error',
        'no-else-return': 'warn',
        'no-eq-null': 'error', // disallow foo == null, require foo === null
        'no-global-assign': 'error', // disallow assignment to native objects or read-only global variables
        'no-implicit-coercion': [
            // disallow the type conversion with shorter notations
            'warn',
            {
                allow: [
                    '+', // includes +value and '' + value
                    '!!',
                    '*',
                ],
            },
        ],
        'no-implicit-globals': 'error', // disallow variable and function declarations in the global scope
        'no-lonely-if': 'warn', // disallow if statements as the only statement in else blocks
        'no-mixed-requires': 'warn', // disallow require calls to be mixed with regular variable declarations
        'no-negated-condition': 'warn',
        'no-new-require': 'error', // disallow new require: var appHeader = new require('app-header');
        'no-path-concat': 'error',
        'no-proto': 'error', // disallow use of __proto__
        // disable no-return-assign until there is an option for disabling this rule
        // for arrow functions. it's causing warning for all react refs currently
        // https://github.com/eslint/eslint/issues/5150
        // 'no-return-assign': 'warn', // disallow assignment in return Statement
        'no-shadow':[ 'warn', {allow: ["props"]}], // disallow variable declarations from shadowing variables declared in the outer scope
        'no-shadow-restricted-names': 'error', // disallow shadowing of restricted names e.g. var undefined = 'foo';
        'no-undef-init': 'warn', // disallow initializing to undefined: var foo = undefined;

        'no-unmodified-loop-condition': 'warn', // disallow loops where the break condition is never valid
        'no-unneeded-ternary': 'warn', // disallow ternary operators when simpler alternatives exist
        'no-unsafe-negation': 'error', // disallow negating the left operand of relational operators: if (!key in object)
        'no-useless-call': 'error', // disallow unnecessary .call() and .apply()
        'no-var': 'warn', // disallow usage of var for variables. use let or const instead
        'no-void': 'error',
        'object-shorthand': 'off', // don't require {a} instead of {a: a}
        'one-var': [
            // require every variable to be declared on separate statement
            'warn',
            'never',
        ],
        'padded-blocks': 'off',
        'prefer-arrow-callback': 'off',
        'prefer-const': [
            // enforce using const instead of let (and var)
            'warn',
            {
                destructuring: 'all', // enforce const for destruction only if all vars can be const
                ignoreReadBeforeAssign: false,
            },
        ],
        'prefer-destructuring': [
            // prefer destucturing for objects
            'warn',
            {
                VariableDeclarator: {
                    object: true,
                    array: true,
                },
                AssignmentExpression: {},
            },
        ],
        'prefer-reflect': 'off',
        'prefer-rest-params': 'error', // require using the rest parameters instead of arguments
        'prefer-spread': 'warn', // prefer spread operator Xyz.func(...args) instead of Xyz.func.apply(Xyz, args)
        'prefer-template': 'off',
        'sort-imports': 'off',
        'sort-keys': 'off',
        'spaced-comment': [
            // require whitespace at the beginning and end of a comment
            'warn',
            'always',
        ],
        'symbol-description': 'error', // require symbol description: Symbol('some description')
        yoda: [
            // disallow yoda conditions: if (1 === b)
            'error',
            'never',
        ],
        'react/prefer-es6-class': 'warn', // prefer ES6 class over React.createReactClass
        'react/prefer-stateless-function': [
            'warn',
            {
                ignorePureComponents: true,
            },
        ],
        'react/sort-prop-types': [
            // warn if proptypes are not sorted
            'warn',
            {
                callbacksLast: true,
            },
        ],
        'react/jsx-key': 'warn', // Warn if an element that likely requires a key prop
        'react/jsx-no-bind': [
            // No .bind() in JSX Props
            'warn',
            {
                ignoreRefs: true,
                allowArrowFunctions: true,
            },
        ],
        'react/jsx-no-duplicate-props': 'error', // prevent duplicate props in JSX
    },
};

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