Data persistence without data loss

Players expect Coin Quest progress to survive sessions, but careless saves can overwrite newer data or turn temporary service failures into data loss.

Only the server accesses DataStoreService. Calls can fail, so pcall contains the failure and the game needs an honest recovery path.

UpdateAsync receives the latest stored value and returns the intended next value. Defaults and schemaVersion make missing or older shapes explicit.

--!strict asks Studio to check your code for type mistakes. It is an instruction for the editor and produces no Output message.

Matching quotes such as "hello" surround a string: a piece of text. The quotation marks tell Luau where the text starts and ends.

local is read as “local”: it creates a name that is available only in the current code scope.

== is read as “equals equals”: it compares two values and produces a boolean.

if is read as “if”: it starts a decision by evaluating a condition.

then is read as “then”: it marks the body that can run when the condition is truthy.

else is read as “else”: it provides the fallback branch.

end is read as “end”: it closes a block such as a decision, loop, or function.

Read one statement at a time: name the value being read, what the operation does, and where its result goes. Keep identifiers exactly as written so you can find them again in the code.

Pause at calls, conditions, and loops. Explain when the body runs before moving to the next statement; use the line notes above when a symbol is unfamiliar.

Start with the statements outside function bodies. A function definition creates a callable value; its body runs when a call, event, or scheduled task reaches it.

Trace the arguments at each call and the branch or loop inside that call. Return to the caller when the function returns. For an event, use the action named in Try it to trigger the callback.

Line 3: DataStoreService is requested only in server code.

Line 4: The store name includes an intentional version boundary.

Line 6: The stored shape has a schema version and coin count.

Line 7: An immutable default handles absent data.

Line 9: The helper returns whether saving succeeded.

Line 11: pcall contains service errors.

Line 12: UpdateAsync receives the latest value for an atomic transform.

Line 13: Runtime checks validate the old shape before reading coins.

Line 14: The returned table is the next stored value.

Before running, identify the starting values and any existing Studio objects this example needs. List what you expect to change.

After your practice change, check this result: Every prior-value case produces a versioned shape, and failures remain visible to server code.

Reading or printing a value leaves it unchanged. Look for assignments, calls that change state, and property updates to explain each change you observe.