Problem Statement
What is the compute() function and when should you use it? How does it work with isolates?
Explanation
The compute() function spawns an isolate, runs a function in that isolate with provided data, and returns a Future with the result, simplifying isolate usage for one-off computations. You pass a top-level or static function and a parameter - compute spawns the isolate, sends the parameter, executes the function, and returns the result. This offloads CPU-intensive work to another isolate preventing UI jank.
Use compute for expensive operations like parsing large JSON (thousands of objects), image processing, compression, complex calculations, or any CPU-intensive work taking more than a few milliseconds. For example, compute(parseJson, jsonString) parses JSON in a separate isolate without blocking UI. The function must be top-level or static because isolates can't access instance methods or closures that capture context.
Data passed to compute is copied between isolates since isolates don't share memory. This copying has overhead, so only use compute when computation cost exceeds copying cost. Don't use compute for simple operations or when data copying is expensive - use it when processing time significantly exceeds transfer time. For repeated processing, consider keeping isolates alive with Isolate.spawn for better performance than compute's spawn-per-call approach.
Compute is Flutter's high-level API for isolates handling spawning, communication, and disposal automatically. For more control, use Isolate.spawn directly with SendPort/ReceivePort for bidirectional communication. Understanding when to use compute versus regular async/await is crucial - most async operations (network, database) are already non-blocking, so reserve compute for true CPU-intensive work.
