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< Orion
Revision as of 18:02, 15 November 2013 by (Talk | contribs) (Rules)

Orion 5.0 will replace our current JSLint validator with ESLint. This page captures ongoing issues.


Here's a table showing the equivalent validation rules in JSLint and ESLint. If a rule has no "JSLint option", then JSLint always enforces it and it cannot be disabled.

ESLint rule JSLint option JSLint message Details
block-scoped-var - '{variable}' is already defined.
  • Occurs when a function-scoped variable is treated as if it was block scoped.
  • ESLint calls this error '{variable} used outside of binding context.'
brace-style - (Not supported)
camelcase - (Not supported)
complexity - (Not supported)
consistent-this - (Not supported)
curly -
  • Statement body should be inside '{ }' braces. (Orion)
  • Expected '{'. (Regular JSLint)
dot-notation sub {a} is better written in dot notation.
eqeqeq eqeqeq or eqeq
  • Expected '===' and saw '=='.
  • Expected '!==' and saw '!='.
  • Newer versions of JSLint call this option eqeqeq.
  • Orion's version calls it eqeq, and inverts the flag's value.
guard-for-in forin The body of a for in should be wrapped in an if statement to filter unwanted properties from the prototype.
max-depth - (Not supported) Enforces max depth of nested blocks within a function.
max-len maxlen Line too long. Enforces a maximum line length.
max-params - (Not supported)
max-statements - (Not supported)
new-cap newcap A constructor name should start with an uppercase letter.
new-parens - Missing '()' invoking a constructor. Flags new Whatever
no-alert devel '{alert, confirm, prompt}' is not defined.
no-bitwise bitwise Unexpected use of '{operator}'. JSLint disallows bitwise ops by default.
no-caller - (Not supported) Flags references to arguments.callee and arguments.caller.
no-comma-dangle - Unexpected comma. Flags trailing commas in object literals.
no-console devel
no-debugger debug All 'debugger' statements should be removed.
no-delete-var - Expected '.' and instead saw ';'. Flags an attempt to delete a local variable.
no-dupe-keys - Duplicate key '{a}'. Flags object literals that contain the same key more than once.
no-empty - (Not supported) Flags an empty block like if (something) { }
no-eq-null - Use '===' to compare with 'null'. JSLint produces a similar warning when comparing against undefined.
no-eval evil eval is evil.
no-ex-assign - Do not assign to the exception parameter.
no-extra-semi - Unnecessary semicolon.
no-label-var - '{label}' is already defined. Flags labels that collide with an identifier.
no-loop-func - Don't make functions within a loop.
no-native-reassign -
  • Read only.
  • Bad assignment. (if assigning to undefined)
Flags an attempt to reassign a native object like Math, Array, undefined, etc.
no-new-array - Use the array literal notation []. Flags new Array()
no-new-object - Use the object literal notation {}.
no-new-wrappers Do not use {String, Number, Boolean, Math, JSON} as a constructor.
no-new - Do not use 'new' for side effects. Flags uses of new operator in an expression that is not assigned to anything.
no-plusplus plusplus
  • Unexpected use of '++'
  • Unexpected use of '--'
no-proto -
  • Reserved name '__proto__'. (if used as an identifier)
  • Stupid key '{a}'. (if used as a key)
Treated as a fatal parse error in JSLint.
no-redeclare - '{a}' is already defined. Usually results from having two for loops in the same function that share a loop variable declaration like var i=....
no-return-assign - (Not supported) Prevents assignment in a return statement.
no-sync stupid Unexpected sync method: '{a}'.
  • Flags Node.js's synchronous I/O methods.
  • The stupid option is supported only in newer versions of JSLint (not Orion's).
no-undef-init - It is not necessary to initialize '{variable}' to 'undefined'.
no-undef undef '{variable}' is not defined.
  • Flags references to a global variable that is not listed in a /*global*/ or /*globals*/ block.
  • Predefined environments (eg. node, browser) can be set in the /*jslint */ block.
no-underscore-dangle nomen Dangling '_'
no-unused-expressions - Expected an assignment or function call and instead saw an expression. Flags expressions that appear in a statement context and don't cause side effects.
no-unused-vars - Function declares unused variable '{a}'. (Orion) Newer JSlint versions have an unparam option which works similarly.
no-use-before-define - '{a}' was used before it was defined.
no-with - Expected an identifier and instead saw 'with'. Treated as fatal parse error in JSLint.
one-var vars
quotes - (Not supported)
radix - Missing radix parameter. Affects parseInt().
regex-spaces - Spaces are hard to count. Use {n}.
semi - Missing semicolon.
strict strict Flags any code that lacks the "use strict" pragma.
use-isnan - Use the isNaN function to compare with NaN.
wrap-iife immed
  • Wrap the entire immediate function invocation in parens.
  • Do not wrap function literals in parens unless they are to be immediately invoked.
  • Move the invocation into the parens that contain the function.
wrap-regex - Wrap the /regexp/ literal in parens to disambiguate the slash operator.

Rule priority

Here are the rules we want, in order of priority:

  1. no-undef

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