This package provides helpers for conveniently triggering dispose/asyncDispose actions using the `using` syntax in JavaScript/TypeScript.
npm install on-disposeThis package provides helpers for conveniently triggering dispose/asyncDispose
actions using the using syntax in JavaScript/TypeScript.
``shIf you're using npm
npm install on-dispose
Usage
A
statement in JavaScript / TypeScript will trigger the method
[Symbol.dispose]() when the object goes out of scope.An
await using statement in JavaScript / TypeScript will trigger the method
[Symbol.asyncDispose]() when the object goes out of scope.Both types of
using statements are similar in behaviour to a
try { ... } finally { ... } statement.on-dispose provides two helper functions onDispose and onAsyncDispose that
accept an action you would like to trigger on dispose / async dispose
respectively without having to define a class or object for it.`ts
import { onDispose, onAsyncDispose } from "on-dispose";// You can use onDispose with a synchronous action in a regular function.
const fn1 = () => {
using _ = onDispose(() => {
console.log("Synchronous dispose action in a synchronous function with using");
})
}
// onDispose also works with a synchronous action in an async function.
const fn2 = async () => {
using _ = onDispose(() => {
console.log("Synchronous dispose action in an async function with using")
})
}
// You can use onAsyncDispose with an asynchronous action in an async function.
const fn3 = async () => {
await using _ = onAsyncDispose(async () => {
console.log("Asynchronous dispose action in an async function with await using")
})
}
// onAsyncDispose also works with a synchronous action.
const fn4 = async () => {
await using _ = onAsyncDispose(() => {
console.log("Synchronous dispose action in an async function with await using")
})
}
const main = async () => {
fn1();
await fn2()
await fn3()
await fn4()
}
void main();
// Will print:
//
// Synchronous dispose action in a synchronous function with using
// Synchronous dispose action in an async function with using
// Asynchronous dispose action in an async function with await using
// Synchronous dispose action in an async function with await using
`> Naturally, you cannot run async dispose actions in regular / non-async
functions.
returns a Disposable object and onAsyncDispose returns an
AsyncDisposable object, so you can also use both with DisposableStack and
AsyncDisposableStack`.