Services · Loom

@rbxts/services needs no configuration: the specifier is aliased to loom’s own service singletons, and every export is the same object game.GetService(...) returns — never a copy.

import { HttpService, RunService, UserInputService } from "@rbxts/services";

HttpService === game.GetService("HttpService"); // true

What loom implements

Service	What loom provides
`CollectionService`	The real tag registry — `AddTag`, `HasTag`, `GetTagged` and the added/removed signals. Code-set tags only; there is no Studio tag editor.
`ContextActionService`	`BindAction` / `BindActionAtPriority` / `UnbindAction` as no-ops.
`Debris`	`AddItem(instance, lifetime)` on a real timer — the instance really is destroyed.
`GuiService`	`SelectedObject` with selection signals, `GetGuiInset`, `ReducedMotionEnabled`.
`HttpService`	`GenerateGUID` and the JSON pair — see below.
`ContentProvider`	`PreloadAsync` and `RequestQueueSize`. Added in 0.12.0.
`Players`	`LocalPlayer` with a pre-built `PlayerGui`, plus `UserId`, `DisplayName` and `GetUserThumbnailAsync` since 0.12.0.
`RunService`	`RenderStepped` / `Heartbeat` / `PostSimulation` / `Stepped`, `BindToRenderStep`, `IsStudio` / `IsRunning` / `IsClient` / `IsServer`.
`StarterGui`	A real container; `SetCore` / `GetCore` / `SetCoreGuiEnabled` / `GetCoreGuiEnabled` as no-ops.
`TextService`	`GetTextSize` / `GetTextBoundsAsync` — see below.
`TweenService`	`Create` and real tween playback — see Animation.
`UserInputService`	Input signals, `GetMouseLocation`, `GetFocusedTextBox`, capability flags, and since 0.12.0 the key and touch state readers (`IsKeyDown`, `GetKeysPressed`, `IsMouseButtonPressed`).
`Workspace`	`CurrentCamera` with a live `ViewportSize`. Reachable as `game.Workspace` since 0.12.0, like every other service.

Then there are the services that are only containers in a client. They are exported as ordinary instances so a tree can be parented into them: Lighting, ReplicatedFirst, ReplicatedStorage, ServerScriptService, ServerStorage, SoundService, StarterPack, StarterPlayer and Teams.

Unimplemented services are exported, and fail where you use them

AnalyticsService, DataStoreService, LocalizationService, LogService, MarketplaceService, MessagingService, PolicyService, Stats, TeleportService and TextChatService are exported but not implemented. Each needs a Roblox server on the other end, and inventing an answer for UserOwnsGamePassAsync would be worse than saying nothing.

They resolve to a warned stub: one console warning at startup, then a throw naming the member on the line that calls it. Leaving the name unexported would be a build error, taking down a preview whose only sin was importing a service beside the ones it uses.

To stand one up yourself, point a shim at @rbxts/services and re-export loom’s singletons alongside your own.

`TextService`

import { TextService } from "@rbxts/services";

const bounds = TextService.GetTextSize(
  "Hello world",
  18,
  Enum.Font.SourceSans,
  new Vector2(200, 1000),
);

GetTextSize(text, fontSize, font, frameSize) measures through the same font stack the renderer paints with. What a component reserves and what the label occupies come from one place. Wrapping is greedy at word boundaries and a zero frameSize.X means “no frame”. GetTextBoundsAsync(params) reads the same measurement off a GetTextBoundsParams instance and does not yield.

The metrics are the browser’s, so shaping and rounding differ from the engine by a glyph here and there. Which typeface answers is the host’s to install. See Fonts and text metrics. The filtering methods are absent: moderation is a server call loom will not make.

`HttpService`

import { HttpService } from "@rbxts/services";

const id = HttpService.GenerateGUID(false);

GenerateGUID(wrapInCurlyBraces?) returns a lowercase RFC 9562 version 4 UUID in canonical 8-4-4-4-12 form. wrapInCurlyBraces defaults to true as in Roblox, so GenerateGUID(false) returns the bare 36 characters.

Entropy comes from the Web Crypto API — crypto.randomUUID() where available (secure contexts only), otherwise crypto.getRandomValues() with the version and variant bits set explicitly. Without Web Crypto it throws rather than generating a weak identifier:

[loom] HttpService.GenerateGUID requires the Web Crypto API

JSONEncode / JSONDecode are JSON.stringify / JSON.parse. Loom’s values are JavaScript values, so what roblox-ts writes as an array or object encodes as it does in Studio. JSONEncode(undefined) yields "null", and a malformed JSONDecode input throws rather than returning undefined.

No networking is implied

A preview never issues requests on your behalf, so GetAsync, PostAsync and RequestAsync throw by name rather than silently doing nothing.

UrlEncode is absent on purpose: the engine encodes more than encodeURIComponent does, and a near-miss encoder is worse than an omission.

Datatype helpers worth knowing

Color3.fromHex accepts exactly six RGB hex digits, either case, with or without one leading #, and converts through the same path as Color3.fromRGB:

const accent = Color3.fromHex("#6366F1");

CSS shorthand, alpha channels, 0x notation and stray whitespace are rejected with a located loom error rather than reinterpreted as another colour.

Color3:ToHex() is its inverse: six lowercase digits with no leading #, each channel clamped and rounded to the nearest 255th.

Color3.fromRGB(99, 102, 241).ToHex(); // "6366f1"
Color3.fromHex(colour.ToHex()) === colour; // by value

ToHSV() destructures as a tuple and Color3.fromHSV(h, s, v) is its inverse. Vector2 carries Unit / Dot / Cross / Lerp / Min / Max / Abs, plus its xAxis / yAxis constants. Vector3 carries the equivalents, and UDim2 a Lerp. UDim has none, because it has none in the engine.