Rule wishlist

[evaera]

This issue will track any rules we'd like to offer for typescript-eslint.

Some of these might already exist as base rules, like no-null-keyword

• [x] Don't allow null
• [x] Don't allow void expression
• [x] Don't allow with statement
• [x] Don't allow debugger statement
• [x] Don't allow == or !=
• [x] Don't allow block labels
• [x] Don't allow regular expressions
• [x] Don't allow accessing function/class prototype or indexing any other value from a function
• [ ] Don't allow yielding outside of async funtions
• [ ] Don't allow reserved Lua keywords
• [ ] Don't allow non-modules (e.g. don't allow global execution mode; must have one import/export)
• [ ] Don't use this outside of an object or class
• [ ] Server/client API access
• [ ] Don't allow exports in non-ModuleScripts
• [ ] ModuleScripts must export
• [ ] Don't allow dynamic import() statement
• [ ] Don't allow use of values typed as any
• [ ] Show invalid identifier names (with odd characters like $) as errors
• [ ] Don't allow rest operator for destructuring

[Validark]

• [x] Don't allow LuaTuples in conditionals without indexing
  • Also, band-aid protect against string.find/match being checked naively (just because I think it is a common and obvious mistake).
    • It is also on my to-do list to add a few more string methods to roblox-ts so string.find doesn't need to be used in TS for every case. https://github.com/roblox-ts/roblox-ts/issues/598
  • [ ] The equivalent error in the roblox-ts compiler can be removed. I think the compiler should only stop you from writing invalid code, and eslint should help you write better code (as well as clue you in when your program would make rbxtsc error)
• [x] Don't allow for..in loops (there is a rule for disallowing for..in array loops we can steal code from)
• [x] Ban the delete operator https://github.com/roblox-ts/roblox-ts/issues/547
• [x] Ban getters/setters https://github.com/roblox-ts/roblox-ts/issues/457
• [x] Disallow arguments (built-in namespace in functions) https://github.com/roblox-ts/roblox-ts/issues/513
• [x] Ban awaiting a never-promise (there is probably a rule for this) https://github.com/roblox-ts/roblox-ts/issues/632 related: https://github.com/roblox-ts/roblox-ts/issues/110
• [x] Automatically fix Vector3/CFrame numeric operators to function calls bearing in mind https://github.com/roblox-ts/roblox-ts/issues/113
  • [ ] Auto-convert unary minus to .mul(-1)
• [ ] Don't allow spreading non-objects https://github.com/roblox-ts/roblox-ts/issues/562
• [ ] Don't allow new methods (static or otherwise, unless Roblox gets first-class functions) https://github.com/roblox-ts/roblox-ts/issues/536
• [ ] Warn developers they should NaN-check from RemoteEvents/RemoteFunctions https://github.com/roblox-ts/roblox-ts/issues/600
• [ ] Don't allow implicitly casting booleans to numbers where applicable
• [ ] Enforce that metamethods are not defined as methods, but member functions https://github.com/roblox-ts/roblox-ts/issues/466
• [ ] Ban destructuring methods from built-in TS namespaces like Object https://github.com/roblox-ts/roblox-ts/issues/425 or Roblox Instances https://github.com/roblox-ts/roblox-ts/issues/465 or strings https://github.com/roblox-ts/roblox-ts/issues/318
• [ ] Ban indexing of non-existing Symbol.iterators https://github.com/roblox-ts/roblox-ts/issues/462
• [ ] Ban using methods which intersect with roblox-ts built-in ones https://github.com/roblox-ts/roblox-ts/issues/420
• [ ] Ban using fake namespaces without calling a method https://github.com/roblox-ts/roblox-ts/issues/366
• [ ] Don't allow spreading or iterating over unioned array | set | map
• [ ] Disallow indexing of unioned array | object https://github.com/roblox-ts/roblox-ts/issues/426
• [ ] Suggest changing arr.insert() at position 0 to arr.unshift(), arr.remove() at last position as arr.pop(), etc
• [ ] Disallow comma expressions with a good explanation for why https://github.com/roblox-ts/roblox-ts/issues/637
• [ ] ? Automatically fix Instance.new or UDim2.new to new Instance and new UDim2, etc
• [ ] ? Automatically change : method call tokens to . (depends on what the AST does with the token)
• [ ] ? Imports should be in scope @rbxts/
• [ ] ? Give a good hint when accessing arbitrary indexes of Instances, e.g. part.InstanceName.InstanceName
• [ ] ? Indexing a nullable type tells you to use an if statement (future, ?.)
• [ ] Force LuaTuple destructuring in variable assignments, e.g. const a = FindPartOnRay() should be const [a] =. Also should work in for loops like gmatch loops.
• [ ] Disallow Object.keys,Object.values,Object.entries,Object.assign, and all other applicable functions which can be used to iterate through the members of Instances, since Instances can't be iterated through at run-time.
• [ ] No in operator on instances, no rest or spread destructuring instances
• [ ] Players.GetChildren should be Players.GetPlayers()

Throwing it out there:

• [ ] ? Disallow LuaTuples being used in user-defined ways. Only allow LuaTuples for built-ins.
• [ ] ? Suggest Object catastrophes be switched to Maps. (index signatures are hard)
• [ ] ? Warn when a number is defined too precisely, e.g. 0.00000000000000000000001
• [ ] ? Discuss disallowing import = require() statements ?

To be determined:

• [ ] Unary plus operator?

[osyrisrblx]

Future Rules

• [ ] Warn to use ?? when using || on a number/string.