files/en-us/web/javascript/reference/global_objects/disposablestack/use/index.md

metadata

title: DisposableStack.prototype.use()
short-title: use()
slug: Web/JavaScript/Reference/Global_Objects/DisposableStack/use
page-type: javascript-instance-method
browser-compat: javascript.builtins.DisposableStack.use
sidebar: jsref

The use() method of {{jsxref("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 be null or undefined.

Return value

The same value that was passed in.

Exceptions

• {{jsxref("TypeError")}}
  • : Thrown if value is not null or undefined, and does not contain a [Symbol.dispose]() method.
• {{jsxref("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 {{jsxref("Statements/using", "using")}} declaration. If the value does not implement the disposable protocol (it doesn't have the [Symbol.dispose]() method), use {{jsxref("DisposableStack/adopt", "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 {{domxref("ReadableStream")}} via a {{domxref("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
}

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}

See also

• JavaScript resource management
• {{jsxref("DisposableStack")}}
• {{jsxref("DisposableStack.prototype.adopt()")}}
• {{jsxref("DisposableStack.prototype.defer()")}}