WaitFor

A simple and safe wait to await the existence of instances.

Roblox's instance tree is ever-changing during runtime due to replication, streaming, and other script-driven changes. As such, it is good to have a safe mechanism to grab either individual or batch instances.

waitForChild

waitForChild<T extends Instance = Instance>(
	parent: Instance,
	childName: string,
	recursive = false,
	timeout = 60,
): Promise<T>

Waits for the childName child to exist within parent. Optionally, a recursive flag can be set to search for the child within all descendants of parent.

If the parent is destroyed, the promise will be rejected with the error WaitForError.Destroyed.

waitForChild(someParent, "SomeChild").then((child) => {
	print(child.GetFullName());
});

waitForChildWhichIsA

waitForChildWhichIsA<T extends keyof Instances>(
	parent: Instance,
	className: T,
	recursive = false,
	timeout = 60,
): Promise<Instance>

Waits for the superclass className to exist within the parent.

waitForChildWhichIsA(someParent, "BasePart").then((part) => {
	print(part.GetFullName());
});

waitForChildOfClass

waitForChildOfClass<T extends keyof Instances>(
	parent: Instance,
	className: T,
	timeout = 60,
): Promise<Instance>

Waits for the given class className to exist within the parent.

waitForChildOfClass(someParent, "PointLight").then((light) => {
	print(light.GetFullName());
});

waitForChildren

waitForChildren(
	parent: Instance,
	childrenNames: string[],
	recursive = false,
	timeout = 60,
): Promise<Instance[]>

Waits for all children childrenNames within parent. Once all children are found, a secondary check is done to make sure none of them were destroyed during the waiting process.

The resolved promise contains an array of children in the same order that they were listed in the childrenNames array.

waitForChildren(vehicle, ["LeftWheel", "RightWheel"]).then((children) => {
	const leftWheel = children[0];
	const rightWheel = children[1];
});

waitForPrimaryPart

waitForPrimaryPart(
	model: Model,
	timeout = 60,
): Promise<BasePart>

Wait for the PrimaryPart of model to exist.

waitForPrimaryPart(someModel).then((primaryPart) => {
	print(primaryPart.GetFullName());
});

waitForObjectValue

waitForObjectValue<T extends Instance = Instance>(
	objectValue: ObjectValue,
	timeout = 60,
): Promise<Instance>

Waits for the value of an ObjectValue to not be nil/undefined.

waitForObjectValue(objectValue).then((value) => {
	print(value);
});

waitForAttribute

waitForAttribute<T>(
	instance: Instance,
	attributeName: string,
	timeout = DEFAULT_TIMEOUT,
): Promise<T>

Waits fot the given attribute to exist.

waitForAttribute<string>(someInstance, "MyString").then((myStr) => {
	print("MyString", myStr);
});

waitForCustom

waitForCustom<T>(
	predicate: () => T | undefined,
	timeout = 60,
): Promise<T>

Waits for the given predicate function to return a non-undefined value.

The predicate function is called every RunService.Heartbeat. As long as the predicate function returns undefined, it will continue to be called every Heartbeat. Once the predicate returns a non-undefined value of type T, the predicate will stop being called and will resolve the promise with the given value.

This can be used for more complex waiting strategies.

waitForCustom(() => {
	const me = Players.FindFirstChild("MyUsername") as Player | undefined;
	return me;
}).then((me) => {
	print(me);
});