A set of general utilities for the lifecycle of a JS/TS project/library
npm install --save lifecycle-utilsThis is an ESM package, so you can only use
importto import it, and cannot userequire
Calling withLock acquires an exclusive lock for the given scope values,
ensuring that its callback cannot run in parallel to any other exclusive or shared lock that use the same scope values.
The order of the values in the scope array is important, and should be consistent across calls to reference the same lock.
You can use as many values as you like, but always ensure that at least one of them is a reference to an object.
import {withLock} from "lifecycle-utils";
const scope = {}; // can be a reference to any object you like
const startTime = Date.now();
async function doSomething(index: number): number {
return await withLock([scope, "myKey"], async () => {
await new Promise(resolve => setTimeout(resolve, 1000));
console.log("index:", index, "time:", Date.now() - startTime);
return 42;
});
}
const res = await Promise.all([
doSomething(1),
doSomething(2),
doSomething(3)
]);
// index: 1 time: 1000
// index: 2 time: 2000
// index: 3 time: 3000
console.log(res); // [42, 42, 42]Check whether a lock is currently active for the given scope values.
import {isLockActive} from "lifecycle-utils";
const scope = {}; // can be a reference to any object you like
const res = isLockActive([scope, "myKey"]);
console.log(res); // falseAcquire an exclusive lock for the given scope values.
import {acquireLock} from "lifecycle-utils";
const scope = {}; // can be a reference to any object you like
const activeLock = await acquireLock([scope, "myKey"]);
console.log("lock acquired");
// ... do some work
activeLock.dispose();Using the using feature of TypeScript is also supported:
import {acquireLock} from "lifecycle-utils";
const scope = {}; // can be a reference to any object you like
{
using lock = await acquireLock([scope, "myKey"]);
console.log("lock acquired");
// ... do some work
}
console.log("lock released");Wait for all locks to be released for a given scope values.
import {waitForLockRelease} from "lifecycle-utils";
const scope = {}; // can be a reference to any object you like
await waitForLockRelease([scope, "myKey"]);
console.log("lock is released");Calling withSharedLock acquires a shared lock for the given scope,
allowing multiple shared locks to run in parallel while preventing an exclusive lock from running at the same time.
Lock requests are acquired in the order they are made, with consecutive shared lock requests acquired together. A new shared lock joins an active shared lock immediately when no regular lock requests are waiting.
import {withLock, withSharedLock} from "lifecycle-utils";
const scope = {}; // can be a reference to any object you like
const sleep = (duration: number) => new Promise((resolve) => setTimeout(resolve, duration));
const exclusive1 = withLock([scope, "myKey"], async () => {
console.log("exclusive 1 started");
await sleep(1000);
console.log("exclusive 1 finished");
});
const shared1 = withSharedLock([scope, "myKey"], async () => {
console.log("shared 1 started");
await sleep(1000);
console.log("shared 1 finished");
});
const shared2 = withSharedLock([scope, "myKey"], async () => {
console.log("shared 2 started");
await sleep(500);
console.log("shared 2 finished");
});
const exclusive2 = withLock([scope, "myKey"], async () => {
console.log("exclusive 2 started");
await sleep(1000);
console.log("exclusive 2 finished");
});
await Promise.all([exclusive1, shared1, shared2, exclusive2]);
// exclusive 1 started
// exclusive 1 finished
// shared 1 started
// shared 2 started
// shared 2 finished
// shared 1 finished
// exclusive 2 started
// exclusive 2 finishedAcquire a shared lock for the given scope values.
Multiple shared locks can be held in parallel, while an exclusive lock cannot be held until every shared lock is released.
Lock requests are acquired in the order they are made, with consecutive shared lock requests acquired together. A new shared lock joins an active shared lock immediately when no regular lock requests are waiting.
import {acquireSharedLock} from "lifecycle-utils";
const scope = {}; // can be a reference to any object you like
const activeLock = await acquireSharedLock([scope, "myKey"]);
console.log("shared lock acquired");
// ... do some work
activeLock.dispose();Using the using feature of TypeScript is also supported:
import {acquireSharedLock} from "lifecycle-utils";
const scope = {}; // can be a reference to any object you like
{
using lock = await acquireSharedLock([scope, "myKey"]);
console.log("shared lock acquired");
// ... do some work
}
console.log("lock released");A simple event relay.
Create a listener with createListener and dispatch events with dispatchEvent.
For each supported event type, create a new instance of EventRelay and expose it as a property.
For example, this code:
import {EventRelay} from "lifecycle-utils";
class MyClass {
public readonly onSomethingHappened = new EventRelay<string>();
public doSomething(whatToDo: string) {
this.onSomethingHappened.dispatchEvent(whatToDo);
console.log("Done notifying listeners");
}
}
const myClass = new MyClass();
myClass.onSomethingHappened.createListener((whatHappened) => {
console.log(`Something happened: ${whatHappened}`);
});
myClass.doSomething("eat a cookie");Will print this:
Something happened: eat a cookie
Done notifying listeners
DisposeAggregator is a utility class that allows you to add multiple items and then dispose them all at once.
You can add a function to call, an object with a dispose method, or an object with a Symbol.dispose method.
To dispose all the items, call dispose or use the Symbol.dispose symbol.
import {DisposeAggregator, EventRelay} from "lifecycle-utils";
const disposeAggregator = new DisposeAggregator();
const eventRelay = new EventRelay<string>();
disposeAggregator.add(eventRelay);
const eventRelay2 = disposeAggregator.add(new EventRelay<string>());
disposeAggregator.dispose();
console.log(eventRelay.disposed === true); // true
console.log(eventRelay2.disposed === true); // trueAsyncDisposeAggregator is a utility class that allows you to add multiple items and then dispose them all at once.
The items are disposed one by one in the order they were added.
You can add a function to call, an object with a dispose method, an object with a Symbol.dispose method,
an object with a Symbol.asyncDispose method, or a Promise that resolves to one of the previous types.
To dispose all the items, call dispose or use the Symbol.asyncDispose symbol.
The difference between AsyncDisposeAggregator and DisposeAggregator is that AsyncDisposeAggregator can dispose async targets.
import {AsyncDisposeAggregator, EventRelay} from "lifecycle-utils";
const disposeAggregator = new AsyncDisposeAggregator();
const eventRelay = new EventRelay<string>();
disposeAggregator.add(eventRelay);
disposeAggregator.add(async () => {
await new Promise(resolve => setTimeout(resolve, 0));
// do some async work
});
disposeAggregator.dispose();An object that provides a .dispose() method that can called only once.
Calling .dispose() will call the provided onDispose function only once.
Any subsequent calls to .dispose() will do nothing.
import {DisposableHandle} from "lifecycle-utils";
function createHandle() {
console.log("allocating resources");
return new DisposableHandle(() => {
console.log("resources disposed");
});
}
const handle = createHandle();
handle.dispose();Using the using feature of TypeScript is also supported:
import {DisposableHandle} from "lifecycle-utils";
function createHandle() {
console.log("allocating resources");
return new DisposableHandle(() => {
console.log("resources disposed");
});
}
function doWork() {
using handle = createHandle();
}
doWork();
// resources disposed
// the dispose function was called since the scope of the `doWork` function endedAn object that provides an async .dispose() method that can called only once.
Calling .dispose() will call the provided onDispose function only once.
Any subsequent calls to .dispose() will do nothing.
import {AsyncDisposableHandle} from "lifecycle-utils";
function createHandle() {
console.log("allocating resources");
return new AsyncDisposableHandle(async () => {
await new Promise(resolve => setTimeout(resolve, 1000));
console.log("resources disposed");
});
}
const handle = createHandle();
await handle.dispose();Using the await using feature of TypeScript is also supported:
import {AsyncDisposableHandle} from "lifecycle-utils";
function createHandle() {
console.log("allocating resources");
return new AsyncDisposableHandle(async () => {
await new Promise(resolve => setTimeout(resolve, 1000));
console.log("resources disposed");
});
}
async function doWork() {
await using handle = createHandle();
}
await doWork();
// resources disposed
// the dispose function was called since the scope of the `doWork` function endedMultiKeyMap is a utility class that works like a Map, but accepts multiple values as the key for each value.
.set(...), .get(...), .has(...), .delete(...) are in time complexity of O(1), given that the length of the keys is constant.
import {MultiKeyMap} from "lifecycle-utils";
type Provider = {name: string};
const provider1: Provider = {name: "1"};
const provider2: Provider = {name: "2"};
const map = new MultiKeyMap<[provider: Provider, name: string], number>();
map.set([provider1, "key1"], 1);
map.set([provider2, "key1"], 2);
map.set([provider1, "key2"], 3);
console.log(map.get([provider1, "key1"])); // 1
console.log(map.get([provider2, "key1"])); // 2
console.log(map.get([provider1, "key2"])); // 3
console.log([...map.keys()]); // [[{name: "1"}, "key1"], [{name: "2"}, "key1"], [{name: "1"}, "key2"]])WeakValueMultiKeyMap is a utility class that works like a MultiKeyMap, but doesn't keep strong references to the values.
When a value is garbage collected, it is automatically removed from the map.
import {WeakValueMultiKeyMap} from "lifecycle-utils";
type Provider = {name: string};
const map = new WeakValueMultiKeyMap<[type: string, name: string], Provider>();
{
const provider1: Provider = {name: "1"};
map.set(["type1", "key1"], provider1);
console.log(map.has(["type1", "key1"])); // true
console.log(map.get(["type1", "key1"])); // {name: "1"}
console.log(map.size); // 1
}
// wait for the runtime to run garbage collection
await new Promise(resolve => setTimeout(resolve, 1000 * 60 * 10));
console.log(map.has(["type1", "key1"])); // false
console.log(map.get(["type1", "key1"])); // undefined
console.log(map.size); // 0WeakValueMap is a utility class that works like a Map, but doesn't keep strong references to the values.
When a value is garbage collected, it is automatically removed from the map.
import {WeakValueMap} from "lifecycle-utils";
type Provider = {name: string};
const map = new WeakValueMap<string, Provider>();
{
const provider1: Provider = {name: "1"};
map.set("provider1", provider1);
console.log(map.has("provider1")); // true
console.log(map.get("provider1")); // {name: "1"}
console.log(map.size); // 1
}
// wait for the runtime to run garbage collection
await new Promise(resolve => setTimeout(resolve, 1000 * 60 * 10));
console.log(map.has("provider1")); // false
console.log(map.get("provider1")); // undefined
console.log(map.size); // 0A timeout that can be set to a delay longer than the maximum timeout delay supported by a regular setTimeout.
import {LongTimeout} from "lifecycle-utils";
const month = 1000 * 60 * 60 * 24 * 7 * 30;
const timeout = new LongTimeout(() => {
console.log("timeout");
}, month);
// to clear the timeout, call dispose
// timeout.dispose();Sets a timeout that can also be set to a delay longer than the maximum timeout delay supported by a regular setTimeout.
You can use clearLongTimeout to clear the timeout.
import {setLongTimeout, clearLongTimeout} from "lifecycle-utils";
const month = 1000 * 60 * 60 * 24 * 7 * 30;
const timeout = setLongTimeout(() => {
console.log("timeout");
}, month);
// to clear the timeout, call clearLongTimeout
// clearLongTimeout(timeout);Clears a timeout that was set with setLongTimeout.
You can also clear a regular timeout with this function.
import {setLongTimeout, clearLongTimeout} from "lifecycle-utils";
const month = 1000 * 60 * 60 * 24 * 7 * 30;
const timeout = setLongTimeout(() => {
console.log("timeout");
}, month);
const timeout2 = setTimeout(() => {
console.log("timeout2");
}, 1000 * 60);
clearLongTimeout(timeout);
clearLongTimeout(timeout2);State is a utility class that allows you to hold a value and notify listeners when the value changes.
import {State} from "lifecycle-utils";
const valueState = new State<number>(6);
const eventHandle = valueState.createChangeListener((newValue, previousValue) => {
console.log("new value:", newValue);
console.log("previous value:", previousValue);
});
valueState.state = 7;
// after a microtask, the listener will be called
// to make event fire immediately upon change, disable the `queueEvents` option on the constructor
await new Promise(resolve => setTimeout(resolve, 0));
// will print:
// new value: 7
// previous value: 6
eventHandle.dispose();Create a listener that listens to multiple states and calls the callback when any of the states change.
import {State} from "lifecycle-utils";
const valueState1 = new State<number>(6);
const valueState2 = new State<string>("hello");
const valueState3 = new State<boolean>(true);
const eventHandle = State.createCombinedChangeListener([valueState1, valueState2, valueState3], (newValues, previousValues) => {
console.log("new values:", newValues);
console.log("previous values:", previousValues);
});
valueState1.state = 7;
valueState2.state = "world";
valueState3.state = false;
// after a microtask, the listener will be called
// to make event fire immediately upon change, disable the `queueEvents` option on the constructor
await new Promise(resolve => setTimeout(resolve, 0));
// will print:
// new values: [7, "world", false]
// previous values: [6, "hello", true]
eventHandle.dispose();Split a text by multiple separators, and return a result of the text and separators.
const parts = splitText("Hello <and> world [then] !", ["<and>", "[then]"]);
console.log(parts); // ["Hello ", new Separator("<and>"), " world ", new Separator("[then]"), " !"]Create a scope exit handle that will call the provided callback when disposed, to be used with using or await using.
For example, this code:
import {scopeExit} from "lifecycle-utils";
function example() {
using exitHandle = scopeExit(() => {
console.log("exiting scope");
});
console.log("inside scope");
}
async function asyncExample() {
await using exitHandle = scopeExit(async () => {
await new Promise((resolve) => setTimeout(resolve, 100));
console.log("exiting async scope");
});
console.log("inside async scope");
}
example();
console.log("example done");
console.log()
await asyncExample();
console.log("asyncExample done");Will print this:
inside scope
exiting scope
example done
inside async scope
exiting async scope
asyncExample done
Register a finalizer for a given target, so that the finalizer is called after the target is garbage-collected.
A finalizer can be a function to call, an object to dispose, or a promise that resolves to one of the previous types.
import {DisposeAggregator, registerFinalizer} from "lifecycle-utils";
const disposeAggregator = new DisposeAggregator();
disposeAggregator.add(() => console.log("disposed"));
let obj: {} | null = {};
registerFinalizer(obj, disposeAggregator);
obj = null; // get rid of a reference to the object
await new Promise((accept) => setTimeout(accept, 1000 * 10)); // wait for the garbage collector
// disposedimport {registerFinalizer} from "lifecycle-utils";
let disposed1 = false;
let disposed2 = false;
let obj: {} | null = {};
const handle1 = registerFinalizer(obj, () => {
disposed1 = true;
});
const handle2 = registerFinalizer(obj, () => {
disposed2 = true;
});
console.log(disposed2.finalized); // false
handle1.dispose(); // remove the finalizer
obj = null; // get rid of a reference to the object
await new Promise((accept) => setTimeout(accept, 1000 * 10)); // wait for the garbage collector
console.log(disposed1); // false, because we removed the finalizer
console.log(disposed2); // true
console.log(disposed2.finalized); // trueTo contribute to lifecycle-utils see CONTRIBUTING.md.
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