Datavized Code Style

Our code style is based on Crockford's, with a few modifications.

The Basics

• Indent with tabs, not spaces
• Always end statements with semicolons
• Conditionals and loops ("if", "while", "for") always use curly braces
• Never use var. Use const wherever possible and let only if necessary.
• Always use "strict equal" (=== and !==, not == or !=)
• Define variables in scope, never global.

The Rules

Stylistic Issues

Rule	Value	Description
array-bracket-spacing		enforce consistent spacing inside array brackets
brace-style		enforce consistent brace style for blocks
camelcase		enforce camelcase naming convention
comma-dangle		require or disallow trailing commas
comma-spacing		enforce consistent spacing before and after commas
comma-style		enforce consistent comma style
indent	tab	enforce consistent indentation
key-spacing		enforce consistent spacing between keys and values in object literal properties
keyword-spacing		enforce consistent spacing before and after keywords
linebreak-style	unix	enforce consistent linebreak style
max-params	5	enforce a maximum number of parameters in function definitions
new-cap		require constructor names to begin with a capital letter
no-array-constructor		disallow Array constructors
no-bitwise		disallow bitwise operators
no-continue		disallow continue statements
no-mixed-spaces-and-tabs		disallow mixed spaces and tabs for indentation
no-trailing-spaces		disallow trailing whitespace at the end of lines
no-underscore-dangle		disallow dangling underscores in identifiers
one-var	never	enforce variables to be declared either together or separately in functions
one-var-declaration-per-line		require or disallow newlines around variable declarations
quote-props	as-needed	require quotes around object literal property names
quotes	single	enforce the consistent use of either backticks, double, or single quotes
semi		require or disallow semicolons instead of ASI
semi-spacing		enforce consistent spacing before and after semicolons
space-before-blocks		enforce consistent spacing before blocks
space-before-function-paren		enforce consistent spacing before function definition opening parenthesis
space-in-parens		enforce consistent spacing inside parentheses
space-infix-ops		require spacing around infix operators
space-unary-ops		enforce consistent spacing before or after unary operators

Best Practices

Rule	Value	Description
babel/no-invalid-this		disallow this keywords outside of classes or class-like objects
block-scoped-var		enforce the use of variables within the scope they are defined
consistent-return		require return statements to either always or never specify values
curly		enforce consistent brace style for all control statements
dot-notation		enforce dot notation whenever possible
eqeqeq		require the use of === and !==
guard-for-in		require for-in loops to include an if statement
no-caller		disallow the use of arguments.caller or arguments.callee
no-case-declarations		disallow lexical declarations in case clauses
no-empty-pattern		disallow empty destructuring patterns
no-eval		disallow the use of eval()
no-extend-native		disallow extending native types
no-fallthrough		disallow fallthrough of case statements
no-global-assign		disallow assignments to native objects or read-only global variables
no-implicit-globals		disallow declarations in the global scope
no-implied-eval		disallow the use of eval()-like methods
no-iterator		disallow the use of the __iterator__ property
no-loop-func		disallow function declarations that contain unsafe references inside loop statements
no-multi-str		disallow multiline strings
no-new		disallow new operators outside of assignments or comparisons
no-new-func		disallow new operators with the Function object
no-octal		disallow octal literals
no-redeclare		disallow variable redeclaration
no-self-assign		disallow assignments where both sides are exactly the same
no-sequences		disallow comma operators
no-unused-labels		disallow unused labels
no-useless-catch		disallow unnecessary catch clauses
no-useless-escape		disallow unnecessary escape characters
no-with		disallow with statements
radix		enforce the consistent use of the radix argument when using parseInt()
require-await		disallow async functions which have no await expression
vars-on-top		require var declarations be placed at the top of their containing scope
wrap-iife	any	require parentheses around immediate function invocations

ECMAScript 6

Rule	Value	Description
constructor-super		require super() calls in constructors
no-class-assign		disallow reassigning class members
no-const-assign		disallow reassigning const variables
no-dupe-class-members		disallow duplicate class members
no-new-symbol		disallow new operators with the Symbol object
no-this-before-super		disallow this/super before calling super() in constructors
no-useless-computed-key		disallow unnecessary computed property keys in objects and classes
no-var		require let or const instead of var
prefer-const		require const declarations for variables that are never reassigned after declared
require-yield		require generator functions to contain yield

Possible Errors

Rule	Value	Description
for-direction		enforce "for" loop update clause moving the counter in the right direction.
getter-return		enforce return statements in getters
no-async-promise-executor		disallow using an async function as a Promise executor
no-compare-neg-zero		disallow comparing against -0
no-cond-assign		disallow assignment operators in conditional expressions
no-constant-condition		disallow constant expressions in conditions
no-control-regex		disallow control characters in regular expressions
no-debugger		disallow the use of debugger
no-dupe-args		disallow duplicate arguments in function definitions
no-dupe-else-if		disallow duplicate conditions in if-else-if chains
no-dupe-keys		disallow duplicate keys in object literals
no-duplicate-case		disallow duplicate case labels
no-empty		disallow empty block statements
no-empty-character-class		disallow empty character classes in regular expressions
no-ex-assign		disallow reassigning exceptions in catch clauses
no-extra-boolean-cast		disallow unnecessary boolean casts
no-extra-parens		disallow unnecessary parentheses
no-extra-semi		disallow unnecessary semicolons
no-func-assign		disallow reassigning function declarations
no-import-assign		disallow assigning to imported bindings
no-inner-declarations		disallow variable or function declarations in nested blocks
no-invalid-regexp		disallow invalid regular expression strings in RegExp constructors
no-irregular-whitespace		disallow irregular whitespace
no-misleading-character-class		disallow characters which are made with multiple code points in character class syntax
no-obj-calls		disallow calling global object properties as functions
no-prototype-builtins		disallow calling some Object.prototype methods directly on objects
no-regex-spaces		disallow multiple spaces in regular expressions
no-setter-return		disallow returning values from setters
no-sparse-arrays		disallow sparse arrays
no-unexpected-multiline		disallow confusing multiline expressions
no-unreachable		disallow unreachable code after return, throw, continue, and break statements
no-unsafe-finally		disallow control flow statements in finally blocks
no-unsafe-negation		disallow negating the left operand of relational operators
require-atomic-updates		disallow assignments that can lead to race conditions due to usage of await or yield
use-isnan		require calls to isNaN() when checking for NaN
valid-typeof		enforce comparing typeof expressions against valid strings

Variables

Rule	Value	Description
no-delete-var		disallow deleting variables
no-restricted-globals	event	disallow specified global variables
no-shadow-restricted-names		disallow identifiers from shadowing restricted names
no-undef		disallow the use of undeclared variables unless mentioned in /*global */ comments
no-unused-vars		disallow unused variables
no-use-before-define		disallow the use of variables before they are defined

Strict Mode

Rule	Value	Description
strict		require or disallow strict mode directives