.eslintrc.json

{
    "settings": {
        "import/resolver": {
            "typescript": {
                "project": ["tsconfig.json", "src/prisma/prismaservice/tsconfig.json"]
            }
        }
    },
    "extends": [
        "next/core-web-vitals",
        "next/typescript",
        "plugin:@typescript-eslint/eslint-recommended",
        "plugin:@typescript-eslint/recommended",
        "plugin:import/recommended",
        "plugin:import/typescript"
    ],
    "parser": "@typescript-eslint/parser",
    "plugins": ["@typescript-eslint", "import"],
    "root": true,
    "rules": {
        "indent": [
            "error",
            4,
            {
                "SwitchCase": 1,
                "VariableDeclarator": 1
            }
        ],
        // require function expressions to have a name
        "func-names": "warn",
        // enforce newline at the end of file, with no multiple empty lines
        "eol-last": "error",  
        // disallow padding inside computed properties, ie. obj[ "fjie"] not allowed
        "computed-property-spacing": [ 
            "error",
            "never"
        ],
        // suggest using arrow functions as callbacks
        "prefer-arrow-callback": "error",
        // suggest using template literals instead of string concatenation
        "prefer-template": "error",
        // disallow modifying variables that are declared using const
        "no-const-assign": "error",
        // disallow symbol constructor
        "no-new-symbol": "error",
        // disallow to use this/super before super() calling in constructors.
        "no-this-before-super": "error",
        // require let or const instead of var
        "no-var": "error",
        // disallow unnecessary constructor
        "no-useless-constructor": "error",
        // require method and property shorthand syntax for object literals
        // ie write obj = { x }, not obj = {x: x}
        "object-shorthand": [
            "error",
            "always"
        ],
        // disallow deletion of variables
        "no-delete-var": "error",
        // disallow labels that share a name with a variable
        "no-label-var": "error",
        // disallow self assignment
        "no-self-assign": "error",
        // disallow shadowing of names such as arguments
        "no-shadow-restricted-names": "error",
        // disallow declaration of variables already declared in the outer scope
        "no-shadow": "error",
        // disallow use of undeclared variables unless mentioned in a /*global */ block
        "no-undef": "error",
        // disallow use of variables before they are defined
        "@typescript-eslint/no-use-before-define": [
            "error",
            {
                "functions": false,
                "classes": false,
                "variables": true,
                "typedefs": false
            }
        ],
        // enforces no braces where they can be omitted
        "arrow-body-style": [
            "error",
            "as-needed"
        ],
        // require space before/after arrow function"s arrow
        "arrow-spacing": [
            "error",
            {
                "before": true,
                "after": true
            }
        ],
        // verify super() callings in constructors
        "constructor-super": "error",
        // disallow modifying variables of class declarations
        "no-class-assign": "error",
        // disallow arrow functions where they could be confused with comparisons
        "no-confusing-arrow": [
            "error",
            {
                "allowParens": true
            }
        ],
        // Require or disallow spaces before/after unary operators
        "space-unary-ops": [
        "error",
        {
            "words": true,
            "nonwords": false
        }
        ],
        "quotes": [
            "error",
            "single",
            "avoid-escape"
        ],
        "jsx-quotes": ["error", "prefer-double"],
        // require camel case names
        "camelcase": [
            "error",
            { 
                "properties": "never" 
            }
        ],
        // enforce spacing before and after comma
        "comma-spacing": [
            "error",
            { 
                "before": false, 
                "after": true 
            }
        ],
        // enforce one true comma style
        "comma-style": [
            "error",
            "last"
        ],
        "key-spacing": [
            "error",
            {
                "beforeColon": false,
                "afterColon": true
            }
        ],
        // require a space before & after certain keywords
        "keyword-spacing": [
            "error",
            {
                "before": true,
                "after": true,
                "overrides": {
                    "return": { "after": true },
                    "throw": { "after": true },
                    "case": { "after": true }
                }
            }
        ],
        // disallow mixed "LF" and "CRLF" as linebreaks
        "linebreak-style": [
            "error",
            "unix"
        ],
        // specify the maximum depth callbacks can be nested
        "max-nested-callbacks": [
            "error",
            3
        ],
        // disallow the omission of parentheses when invoking a constructor with no arguments
        "new-parens": "error",
        // enforces new line after each method call in the chain to make it
        // more readable and easy to maintain
        "newline-per-chained-call": [
            "error",
            { 
                "ignoreChainWithDepth": 4
            }
        ],
        // disallow use of the Array constructor
        "no-array-constructor": "error",
        // disallow use of the continue statement
        "no-continue": "warn",
        // disallow if as the only statement in an else block
        "no-lonely-if": "error",
        // disallow mixed spaces and tabs for indentation
        "no-mixed-spaces-and-tabs": "error",
        // disallow multiple empty lines and only one newline at the end
        "no-multiple-empty-lines": [
            "error",
            {
                "max": 2,
                "maxEOF": 1
            }
        ],
        // disallow nested ternary expressions
        "no-nested-ternary": "error",
        // disallow use of the Object constructor
        "no-new-object": "error",
        // disallow trailing whitespace at the end of lines
        "no-trailing-spaces": "error",
        // disallow the use of Boolean literals in conditional expressions
        // also, prefer `a || b` over `a ? a : b`
        "no-unneeded-ternary": [
            "error",
            {
                "defaultAssignment": true
            }
        ],
        // disallow whitespace before properties
        "no-whitespace-before-property": "error",
        // require padding inside curly braces
        "object-curly-spacing": [
            "error",
            "always"
        ],
        // require a newline around variable declaration
        "one-var-declaration-per-line": [
            "error",
            "always"
        ],
        // enforce padding within blocks
        "padded-blocks": [
            "error",
            "never"
        ],
        // require quotes around object literal property names
        "quote-props": [
            "warn",
            "as-needed",
            {
                "keywords": false,
                "unnecessary": true,
                "numbers": false
            }
        ],
        // specify whether double or single quotes should be used
        // require or disallow use of semicolons instead of ASI
        "semi": [
            "error",
            "never"
        ],
        // require or disallow space before blocks
        "space-before-blocks": "error",
        // require or disallow space before function opening parenthesis
        "space-before-function-paren": [
            "error",
            {
                "anonymous": "always",
                "named": "never"
            }
        ],
        // require or disallow spaces inside parentheses
        "space-in-parens": [
            "error",
            "never"
        ],
        // require spaces around operators
        "space-infix-ops": "error",
        // enforces return statements in callbacks of array"s methods
        "array-callback-return": "error",
        // require return statements to either always or never specify values
        "consistent-return": "error",
        // specify curly brace conventions for all control statements
        "curly": [
            "error",
            "multi-line"
        ],
        // require default case in switch statements
        "default-case": "error",
        // encourages use of dot notation whenever possible
        "dot-notation": "error",
        // require the use of === and !==
        "eqeqeq": "error",
        // make sure for-in loops have 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/default clauses
        "no-case-declarations": "error",
        // disallow else after a return in an if
        "no-else-return": "error",
        // disallow Unnecessary Labels
        "no-extra-label": "error",
        // disallow comparisons to null without a type-checking operator
        "no-eq-null": "error",
        // disallow use of eval()
        "no-eval": "error",
        // disallow adding to native types
        "no-extend-native": "error",
        // disallow unnecessary function binding
        "no-extra-bind": "error",
        // disallow fallthrough of case statements
        "no-fallthrough": "error",
        // disallow the use of leading or trailing decimal points in numeric literals
        "no-floating-decimal": "error",
        // disallow use of eval()-like methods
        "no-implied-eval": "error",
        // disallow this keywords outside of classes or class-like objects
        "no-iterator": "error",
        // disallow use of labels for anything other then loops and switches
        "no-labels": [
            "error",
            {
                "allowLoop": false,
                "allowSwitch": false
            }
        ],
        // disallow unnecessary nested blocks
        "no-lone-blocks": "error",
        // disallow creation of functions within loops
        "no-loop-func": "error",
        // disallow use of multiple spaces
        "no-multi-spaces": "error",
        // disallow use of multiline strings
        "no-multi-str": "error",
        // disallow reassignments of native objects
        "no-native-reassign": "error",
        // disallow use of new operator when not part of the assignment or comparison
        "no-new": "error",
        // disallow use of new operator for Function object
        "no-new-func": "error",
        // disallows creating new instances of String,Number, and Boolean
        "no-new-wrappers": "error",
        // disallow use of (old style) octal literals
        "no-octal": "error",
        // disallow use of octal escape sequences in string literals, such as
        // var foo = "Copyright \251";
        "no-octal-escape": "error",
        // disallow reassignment of function parameters
        // disallow parameter object manipulation
        "no-param-reassign": [
            "warn",
            {
                "props": false
            }
        ],
        // disallow usage of __proto__ property
        "no-proto": "error",
        // disallow use of assignment in return statement
        "no-return-assign": "error",
        // disallow use of `javascript:` urls.
        "no-script-url": "error",
        // disallow comparisons where both sides are exactly the same
        "no-self-compare": "error",
        // disallow use of comma operator
        "no-sequences": "error",
        // disallow usage of expressions in statement position
        "no-unused-expressions": "error",
        // disallow unused labels
        "no-unused-labels": "error",
        // disallow usage of configurable warning terms in comments: e.g. todo
        "no-warning-comments": [
            "warn",
            {
                "terms": ["todo", "fixme", "xxx"],
                "location": "start"
            }
        ],
        // disallow use of the with statement
        "no-with": "error",
        // require use of the second argument for parseInt()
        "radix": "error",
        // require immediate function invocation to be wrapped in parentheses
        "wrap-iife": [
            "error",
            "outside"
        ],
        // require or disallow Yoda conditions
        "yoda": "error",
        // disallow assignment in conditional expressions
        "no-cond-assign": [
            "error",
            "always"
        ],
        // disallow use of constant expressions in conditions
        "no-constant-condition": "warn",
        // disallow control characters in regular expressions
        "no-control-regex": "error",
        // disallow use of debugger
        "no-debugger": "warn",
        // disallow duplicate arguments in functions
        "no-dupe-args": "error",
        // disallow duplicate keys when creating object literals
        "no-dupe-keys": "error",
        // disallow a duplicate case label.
        "no-duplicate-case": "error",
        // disallow the use of empty character classes in regular expressions
        "no-empty-character-class": "error",
        // disallow empty statements
        "no-empty": "error",
        // disallow assigning to the exception in a catch block
        "no-ex-assign": "error",
        // disallow double-negation boolean casts in a boolean context
        "no-extra-boolean-cast": "error",
        // disallow unnecessary parentheses
        "no-extra-parens": [
            "error",
            "functions"
        ],
        // disallow unnecessary semicolons
        "no-extra-semi": "error",
        // disallow overwriting functions written as function declarations
        "no-func-assign": "error",
        // disallow function or variable declarations in nested blocks
        "no-inner-declarations": "error",
        // disallow invalid regular expression strings in the RegExp constructor
        "no-invalid-regexp": "error",
        // disallow irregular whitespace outside of strings and comments
        "no-irregular-whitespace": "error",
        // disallow negation of the left operand of an in expression
        "no-negated-in-lhs": "error",
        // disallow the use of object properties of the global object (Math and JSON) as functions
        "no-obj-calls": "error",
        // disallow multiple spaces in a regular expression literal
        "no-regex-spaces": "error",
        // disallow sparse arrays
        "no-sparse-arrays": "error",
        // disallow unreachable statements after a return, throw, continue, or break statement
        "no-unreachable": "error",
        // disallow comparisons with the value NaN
        "use-isnan": "error",
        // ensure that the results of typeof are compared against a valid string
        "valid-typeof": "error",
        // Avoid code that looks like two expressions but is actually one
        "no-unexpected-multiline": "error",
        // specify the maximum depth that blocks can be nested
        "max-depth": [
            "error",
            4
        ],
        // limits the number of parameters that can be used in the function declaration.
        "max-params": [
            "error",
            4
        ],
        // disallow use of bitwise operators
        "no-bitwise": "warn",
        // enforce return after a callback
        "callback-return": "error",
        // enforces error handling in callbacks (node environment)
        "handle-callback-err": "error",
        // disallow mixing regular variable and require declarations
        "no-mixed-requires": [
            "error",
            {
                "grouping": true, 
                "allowCall": true 
            }
        ],
        // disallow use of new operator with the require function
        "no-new-require": "error",
        // disallow string concatenation with __dirname and __filename
        "no-path-concat": "error",
        // disallow process.exit()
        "no-process-exit": "error",
        // disallow use of synchronous methods (off by default)
        "no-sync": "error",
        // enforce spacing inside array brackets
        "array-bracket-spacing": [
            "error",
            "never"
        ],
        // enforce one true brace style
        "brace-style": [
            "error",
            "1tbs", 
            { 
                "allowSingleLine": true 
            }
        ],
        // enforce max length of lines
        "max-len": [
            "error",
            {
                "code": 125
            }
        ],
        // dissallow relative imports (e.g. '../'), imports from same folder are stil allowed
        "no-restricted-imports": [
            "error",
            {
                "patterns": [
                    {
                        "group": ["../"],
                        "message": "Relative imports are not allowed."
                    }
                ]
            }
        ],
        // import statement order
        "import/order": [
            "warn",
            {
                "groups": [
                    "index",
                    "sibling",
                    "parent",
                    "internal",
                    "external",
                    "builtin",
                    "object",
                    "type"
                ]
            }
        ],
        "@typescript-eslint/consistent-type-imports": [
            "error",
            {
                "prefer": "type-imports"
            }
        ],

        //SOME ODD OPTIONS:
        // suggest using the spread operator instead of .apply()
        "prefer-spread": "error",
        // suggest using Reflect methods where applicable
        "prefer-reflect": "error",
        // use rest parameters instead of arguments
        "prefer-rest-params": "error",
        // enforce usage of spacing in template strings
        "template-curly-spacing": "error",
        // disable next js warning for using <img>
        "@next/next/no-img-element": "off"
    }
}