javascript instance method
DisposableStack.prototype.use()
The use() method of DisposableStack instances registers a value that implements the disposable protocol to the stack.
Syntax
use(value)
Parameters
value- : The value to register to the stack. Must either contain a
[Symbol.dispose]()method, or benullorundefined.
- : The value to register to the stack. Must either contain a
Return value
The same value that was passed in.
Exceptions
TypeError- : Thrown if
valueis notnullorundefined, and does not contain a[Symbol.dispose]()method.
- : Thrown if
ReferenceError- : Thrown if the stack is already disposed.
Description
The primary purpose of use() is to register a value that implements the disposable protocol to the stack, as the equivalent of the using declaration. If the value does not implement the disposable protocol (it doesn’t have the [Symbol.dispose]() method), use adopt() instead, passing a callback that calls the resource’s cleanup method.
You should make your resource registered as soon as it’s declared. This means you should always wrap your resource acquisition expression in use(), instead of extracting it to a separate statement.
using disposer = new DisposableStack();
const reader = stream.getReader();
disposer.use(reader);
Examples
Using use()
This code consumes a ReadableStream via a ReadableStreamDefaultReader. The reader is automatically closed when the function completes, assuming it implements a [Symbol.dispose]() method that synchronously releases the lock on the stream.
{
using disposer = new DisposableStack();
const reader = disposer.use(stream.getReader());
const { value, done } = reader.read();
if (!done) {
// Process the value
}
// The reader.releaseLock() method is called here before exiting
}