Luau Patterns

When to Load

Load when choosing a module shape, owning Roblox instances or event connections, scheduling work, or preserving failure semantics. Use roblox-luau-core for language behavior, roblox-luau-types for types, and roblox-architecture for project-wide ownership and startup.

Quick Reference

Choose the smallest shape

• Plain functions: default for stateless transformation or validation.
• Module with private state: one explicit subsystem owner. Do not create a manager class merely to namespace functions.
• Object with metatable: multiple independent values need shared behavior and lifecycle.
• Existing library abstraction: follow it when the project already uses it consistently. Do not add Promise, signal, cleanup, or framework dependencies for one call site.

Constructors use ., instance methods use :, and mutable fields belong on the instance, not the class table.

Make ownership visible

The code that connects a signal, creates an instance, or starts a task owns cleanup. Store connections and cancel or disconnect them when it ends.

Configure an instance before parenting when observers should not see partial state. Parent earlier only when the API or lifecycle requires ancestry, and document that reason. This is visibility control, not a magic replication-race fix.

Preserve failure semantics

local ok, value = pcall(dataStore.GetAsync, dataStore, key)
if not ok then
    return nil, `read failed: {value}`
end
return value, nil -- value may legitimately be nil

Do not collapse "call succeeded and returned nil" into "call failed." Retry only when the domain operation is safe to repeat. Persistence, HTTP, purchases, and remotes belong to their domain skills.

Schedule deliberately

Use task.defer, task.spawn, task.delay, and task.cancel deliberately. Avoid legacy wait() and unjustified polling. Prefer a real state-change signal; otherwise choose and measure an explicit cadence.

Review

Clear owner, narrow public API, no circular require, no accidental concurrent startup, success and missing-data states remain distinct, connections/tasks cleaned up, client input routed to roblox-networking.

Detailed decision rules and lifecycle examples: references/full.md