enforceBeforeAfterdeprecatedHooksallowDeprecatednpm install hookified --save
This was built because we constantly wanted hooks and events extended on libraires we are building such as Keyv and Cacheable. This is a simple way to add hooks and events to your classes.
import { Hookified } from 'hookified';
class MyClass extends Hookified {
constructor() {
super();
}
async myMethodEmittingEvent() {
this.emit('message', 'Hello World');
}
//with hooks you can pass data in and if they are subscribed via onHook they can modify the data
async myMethodWithHooks(): Promise<any> {
let data = { some: 'data' };
// do something
await this.hook('before:myMethod2', data);
return data;
}
}
You can even pass in multiple arguments to the hooks:
import { Hookified } from 'hookified';
class MyClass extends Hookified {
constructor() {
super();
}
async myMethodWithHooks(): Promise<any> {
let data = { some: 'data' };
let data2 = { some: 'data2' };
// do something
await this.hook('before:myMethod2', data, data2);
return data;
}
}
<script type="module">
import { Hookified } from 'https://cdn.jsdelivr.net/npm/hookified/dist/browser/index.js';
class MyClass extends Hookified {
constructor() {
super();
}
async myMethodEmittingEvent() {
this.emit('message', 'Hello World');
}
//with hooks you can pass data in and if they are subscribed via onHook they can modify the data
async myMethodWithHooks(): Promise<any> {
let data = { some: 'data' };
// do something
await this.hook('before:myMethod2', data);
return data;
}
}
</script>
if you are not using ESM modules, you can use the following:
<script src="https://cdn.jsdelivr.net/npm/hookified/dist/browser/index.global.js"></script>
<script>
class MyClass extends Hookified {
constructor() {
super();
}
async myMethodEmittingEvent() {
this.emit('message', 'Hello World');
}
//with hooks you can pass data in and if they are subscribed via onHook they can modify the data
async myMethodWithHooks(): Promise<any> {
let data = { some: 'data' };
// do something
await this.hook('before:myMethod2', data);
return data;
}
}
</script>
The Hook class provides a convenient way to create hook entries. It implements the IHook interface.
The IHook interface has the following properties:
| Property | Type | Required | Description |
|---|---|---|---|
id | string | No | Unique identifier for the hook. Auto-generated via crypto.randomUUID() if not provided. |
event | string | Yes | The event name for the hook. |
handler | HookFn | Yes | The handler function for the hook. |
When a hook is registered, it is assigned an id (auto-generated if not provided). The id can be used to look up or remove hooks via getHook and removeHookById. If you register a hook with the same id on the same event, it will replace the existing hook in-place (preserving its position).
Using the Hook class:
import { Hook, Hookified } from 'hookified';
class MyClass extends Hookified {
constructor() { super(); }
}
const myClass = new MyClass();
// Without id (auto-generated)
const hook = new Hook('before:save', async (data) => {
data.validated = true;
});
// With id
const hook2 = new Hook('after:save', async (data) => {
console.log('saved');
}, 'my-after-save-hook');
// Register with onHook
myClass.onHook(hook);
// Or register multiple hooks with onHooks
const hooks = [
new Hook('before:save', async (data) => { data.validated = true; }),
new Hook('after:save', async (data) => { console.log('saved'); }),
];
myClass.onHooks(hooks);
// Remove hooks
myClass.removeHooks(hooks);
Using plain TypeScript with the IHook interface:
import { Hookified, type IHook } from 'hookified';
class MyClass extends Hookified {
constructor() { super(); }
}
const myClass = new MyClass();
const hook: IHook = {
id: 'my-validation-hook', // optional — auto-generated if omitted
event: 'before:save',
handler: async (data) => {
data.validated = true;
},
};
const stored = myClass.onHook(hook);
console.log(stored?.id); // 'my-validation-hook'
// Later, remove by id
myClass.removeHookById('my-validation-hook');
The WaterfallHook class chains multiple hook functions sequentially in a waterfall pipeline. Each hook receives a context containing the original arguments and the accumulated results from all previous hooks. It implements the IHook interface, so it integrates directly with Hookified.onHook().
The WaterfallHookContext has the following properties:
| Property | Type | Description |
|---|---|---|
initialArgs | any | The original arguments passed to the waterfall execution. |
results | WaterfallHookResult[] | Array of { hook, result } entries from previous hooks. Empty for the first hook. |
Basic usage:
import { WaterfallHook } from 'hookified';
const wh = new WaterfallHook('process', ({ results, initialArgs }) => {
// Final handler receives all accumulated results
const lastResult = results[results.length - 1].result;
console.log('Final:', lastResult);
});
// Add transformation hooks to the pipeline
wh.addHook(({ initialArgs }) => {
return initialArgs + 1; // 5 -> 6
});
wh.addHook(({ results }) => {
return results[results.length - 1].result * 2; // 6 -> 12
});
// Execute the waterfall by calling handler directly
await wh.handler(5); // Final: 12
Integrating with Hookified via onHook():
import { Hookified, WaterfallHook } from 'hookified';
class MyClass extends Hookified {
constructor() { super(); }
}
const myClass = new MyClass();
const wh = new WaterfallHook('save', ({ results }) => {
const data = results[results.length - 1].result;
console.log('Saved:', data);
});
wh.addHook(({ initialArgs }) => {
return { ...initialArgs, validated: true };
});
wh.addHook(({ results }) => {
return { ...results[results.length - 1].result, timestamp: Date.now() };
});
// Register with Hookified — works because WaterfallHook implements IHook
myClass.onHook(wh);
// When hook() fires, the full waterfall pipeline executes
await myClass.hook('save', { name: 'test' });
// Saved: { name: 'test', validated: true, timestamp: ... }
Managing hooks:
const wh = new WaterfallHook('process', ({ results }) => results);
const myHook = ({ initialArgs }) => initialArgs + 1;
wh.addHook(myHook);
// Remove a hook by reference
wh.removeHook(myHook); // returns true
// Access the hooks array
console.log(wh.hooks.length); // 0
All examples below assume the following setup unless otherwise noted:
import { Hookified } from 'hookified'; class MyClass extends Hookified { constructor(options) { super(options); } } const myClass = new MyClass();
Controls whether deprecated hooks are allowed to be registered and executed. Default is true. When set to false, deprecated hooks will still emit warnings but will be prevented from registration and execution.
import { Hookified } from 'hookified';
const deprecatedHooks = new Map([
['oldHook', 'Use newHook instead']
]);
class MyClass extends Hookified {
constructor() {
super({ deprecatedHooks, allowDeprecated: false });
}
}
const myClass = new MyClass();
console.log(myClass.allowDeprecated); // false
// Listen for deprecation warnings (still emitted even when blocked)
myClass.on('warn', (event) => {
console.log(`Warning: ${event.message}`);
});
// Try to register a deprecated hook - will emit warning but not register
myClass.onHook({ event: 'oldHook', handler: () => {
console.log('This will never execute');
}});
// Output: Warning: Hook "oldHook" is deprecated: Use newHook instead
// Verify hook was not registered
console.log(myClass.getHooks('oldHook')); // undefined
// Try to execute a deprecated hook - will emit warning but not execute
await myClass.hook('oldHook');
// Output: Warning: Hook "oldHook" is deprecated: Use newHook instead
// (but no handlers execute)
// Non-deprecated hooks work normally
myClass.onHook({ event: 'validHook', handler: () => {
console.log('This works fine');
}});
console.log(myClass.getHooks('validHook')); // [handler function]
// You can dynamically change the setting
myClass.allowDeprecated = true;
// Now deprecated hooks can be registered and executed
myClass.onHook({ event: 'oldHook', handler: () => {
console.log('Now this works');
}});
console.log(myClass.getHooks('oldHook')); // [handler function]
Behavior when allowDeprecated is false:
onHook, addHook, prependHook, etc.) will emit warnings but skip registrationhook, callHook) will emit warnings but skip executionremoveHook, removeHooks, and getHooks always work regardless of deprecation statusallowDeprecated settingUse cases:
allowDeprecated: true to maintain functionality while seeing warningsallowDeprecated: false to ensure no deprecated hooks are accidentally usedA Map of deprecated hook names to deprecation messages. When a deprecated hook is used, a warning will be emitted via the 'warn' event and logged to the logger (if available). Default is an empty Map.
import { Hookified } from 'hookified';
// Define deprecated hooks with custom messages
const deprecatedHooks = new Map([
['oldHook', 'Use newHook instead'],
['legacyMethod', 'This hook will be removed in v2.0'],
['deprecatedFeature', ''] // Empty message - will just say "deprecated"
]);
class MyClass extends Hookified {
constructor() {
super({ deprecatedHooks });
}
}
const myClass = new MyClass();
console.log(myClass.deprecatedHooks); // Map with deprecated hooks
// Listen for deprecation warnings
myClass.on('warn', (event) => {
console.log(`Deprecation warning: ${event.message}`);
// event.hook contains the hook name
// event.message contains the full warning message
});
// Using a deprecated hook will emit warnings
myClass.onHook({ event: 'oldHook', handler: () => {
console.log('This hook is deprecated');
}});
// Output: Hook "oldHook" is deprecated: Use newHook instead
// Using a deprecated hook with empty message
myClass.onHook({ event: 'deprecatedFeature', handler: () => {
console.log('This hook is deprecated');
}});
// Output: Hook "deprecatedFeature" is deprecated
// You can also set deprecated hooks dynamically
myClass.deprecatedHooks.set('anotherOldHook', 'Please migrate to the new API');
// Works with logger if provided
import pino from 'pino';
const logger = pino();
const myClassWithLogger = new Hookified({
deprecatedHooks,
eventLogger: logger
});
// Deprecation warnings will be logged to logger.warn
The deprecation warning system applies to the following hook-related methods:
onHook(), addHook(), onHooks(), prependHook(), onceHook(), prependOnceHook()hook(), callHook()Note: getHooks(), removeHook(), and removeHooks() do not check for deprecated hooks and always operate normally.
Deprecation warnings are emitted in two ways:
{ hook: string, message: string }eventLogger.warn() if an eventLogger is configured and has a warn methodIf set to true, enforces that all hook names must start with 'before' or 'after'. This is useful for maintaining consistent hook naming conventions in your application. Default is false.
import { Hookified } from 'hookified';
class MyClass extends Hookified {
constructor() {
super({ enforceBeforeAfter: true });
}
}
const myClass = new MyClass();
console.log(myClass.enforceBeforeAfter); // true
// These will work fine
myClass.onHook({ event: 'beforeSave', handler: async () => {
console.log('Before save hook');
}});
myClass.onHook({ event: 'afterSave', handler: async () => {
console.log('After save hook');
}});
myClass.onHook({ event: 'before:validation', handler: async () => {
console.log('Before validation hook');
}});
// This will throw an error
try {
myClass.onHook({ event: 'customEvent', handler: async () => {
console.log('This will not work');
}});
} catch (error) {
console.log(error.message); // Hook event "customEvent" must start with "before" or "after" when enforceBeforeAfter is enabled
}
// You can also change it dynamically
myClass.enforceBeforeAfter = false;
myClass.onHook({ event: 'customEvent', handler: async () => {
console.log('This will work now');
}});
The validation applies to all hook-related methods:
onHook(), addHook(), onHooks()prependHook(), onceHook(), prependOnceHook()hook(), callHook()getHooks(), removeHook(), removeHooks()Note: The beforeHook() and afterHook() helper methods automatically generate proper hook names and work regardless of the enforceBeforeAfter setting.
If set, errors thrown in hooks will be logged to the logger. If not set, errors will be only emitted.
import pino from 'pino';
const myClass = new MyClass({ eventLogger: pino() });
myClass.onHook({ event: 'before:myMethod2', handler: async () => {
throw new Error('error');
}});
// when you call before:myMethod2 it will log the error to the logger
await myClass.hook('before:myMethod2');
Get all hooks. Returns a Map<string, IHook[]> where each key is an event name and the value is an array of IHook objects.
myClass.onHook({ event: 'before:myMethod2', handler: async (data) => {
data.some = 'new data';
}});
console.log(myClass.hooks); // Map { 'before:myMethod2' => [{ event: 'before:myMethod2', handler: [Function] }] }
If set to true, errors thrown in hooks will be thrown. If set to false, errors will be only emitted.
const myClass = new MyClass({ throwOnHookError: true });
console.log(myClass.throwOnHookError); // true
try {
myClass.onHook({ event: 'error-event', handler: async () => {
throw new Error('error');
}});
await myClass.hook('error-event');
} catch (error) {
console.log(error.message); // error
}
myClass.throwOnHookError = false;
console.log(myClass.throwOnHookError); // false
Controls whether hook objects are cloned before storing internally. Default is true. When true, a shallow copy of the IHook object is stored, preventing external mutation from affecting registered hooks. When false, the original reference is stored directly.
const myClass = new MyClass({ useHookClone: false });
const hook = { event: 'before:save', handler: async (data) => {} };
myClass.onHook(hook);
// With useHookClone: false, the stored hook is the same reference
const storedHooks = myClass.getHooks('before:save');
console.log(storedHooks[0] === hook); // true
// You can dynamically change the setting
myClass.useHookClone = true;
This is an alias for .onHook() that takes an event name and handler function directly.
myClass.addHook('before:myMethod2', async (data) => {
data.some = 'new data';
});
This is a helper function that will prepend a hook name with after:.
// Inside your class method — the event name will be `after:myMethod2`
await this.afterHook('myMethod2', data);
This is a helper function that will prepend a hook name with before:.
// Inside your class method — the event name will be `before:myMethod2`
await this.beforeHook('myMethod2', data);
This is an alias for .hook(eventName, ...args) for backwards compatibility.
Clear all hooks across all events.
myClass.onHook({ event: 'before:myMethod2', handler: async (data) => {
data.some = 'new data';
}});
myClass.clearHooks();
Get a specific hook by id, searching across all events. Returns the IHook if found, or undefined.
const myClass = new MyClass();
myClass.onHook({
id: 'my-hook',
event: 'before:save',
handler: async (data) => { data.validated = true; },
});
const hook = myClass.getHook('my-hook');
console.log(hook?.id); // 'my-hook'
console.log(hook?.event); // 'before:save'
console.log(hook?.handler); // [Function]
Get all hooks for an event. Returns an IHook[] array, or undefined if no hooks are registered for the event.
myClass.onHook({ event: 'before:myMethod2', handler: async (data) => {
data.some = 'new data';
}});
console.log(myClass.getHooks('before:myMethod2')); // [{ event: 'before:myMethod2', handler: [Function] }]
Run a hook event.
// Inside your class method
await this.hook('before:myMethod2', data);
You can pass multiple arguments to the hook:
// Inside your class method
await this.hook('before:myMethod2', data, data2);
// The handler receives all arguments
myClass.onHook({ event: 'before:myMethod2', handler: async (data, data2) => {
data.some = 'new data';
data2.some = 'new data2';
}});
Run a hook event synchronously. Async handlers (functions declared with async keyword) are silently skipped and only synchronous handlers are executed.
Note: The
.hook()method is preferred as it executes both sync and async functions. Use.hookSync()only when you specifically need synchronous execution.
// This sync handler will execute
myClass.onHook({ event: 'before:myMethod', handler: (data) => {
data.some = 'modified';
}});
// This async handler will be silently skipped
myClass.onHook({ event: 'before:myMethod', handler: async (data) => {
data.some = 'will not run';
}});
// Inside your class method
this.hookSync('before:myMethod', data); // Only sync handler runs
Subscribe to a hook event. Supports two calling styles:
onHook(hook, options?) — takes an IHook object and an optional OnHookOptions object.onHook(event, handler) — takes an event name string and a handler function (v1-compatible).Returns the stored IHook (with id assigned), or undefined if the hook was blocked by deprecation. The returned reference is the exact object stored internally, which is useful for later removal with .removeHook() or .removeHookById(). To register multiple hooks at once, use .onHooks().
If the hook has an id, it will be used as-is. If not, a UUID is auto-generated via crypto.randomUUID(). If a hook with the same id already exists on the same event, it will be replaced in-place (preserving its position in the array).
Options (OnHookOptions):
useHookClone (boolean, optional) — Per-call override for the instance-level useHookClone setting. When true, the hook object is cloned before storing. When false, the original reference is stored directly. When omitted, falls back to the instance-level setting.position ("Top" | "Bottom" | number, optional) — Controls where the hook is inserted in the handlers array. "Top" inserts at the beginning, "Bottom" appends to the end (default). A number inserts at that index, clamped to the array bounds.// Single hook — returns the stored IHook with id
const stored = myClass.onHook({
event: 'before:myMethod2',
handler: async (data) => {
data.some = 'new data';
},
});
console.log(stored.id); // auto-generated UUID
// With a custom id
const stored2 = myClass.onHook({
id: 'my-validation',
event: 'before:save',
handler: async (data) => { data.validated = true; },
});
// Replace hook by registering with the same id
myClass.onHook({
id: 'my-validation',
event: 'before:save',
handler: async (data) => { data.validated = true; data.extra = true; },
});
// Only one hook with id 'my-validation' exists, at the same position
// Remove by id
myClass.removeHookById('my-validation');
// Use the returned reference to remove the hook later
myClass.removeHook(stored);
// Override useHookClone per-call — store original reference even though instance default is true
const hook = { event: 'before:save', handler: async (data) => {} };
myClass.onHook(hook, { useHookClone: false });
console.log(myClass.getHooks('before:save')[0] === hook); // true
// Insert at the top of the handlers array
myClass.onHook({ event: 'before:save', handler: async (data) => {} }, { position: 'Top' });
// Insert at a specific index
myClass.onHook({ event: 'before:save', handler: async (data) => {} }, { position: 1 });
// Shorthand form — pass event name and handler directly (v1-compatible)
myClass.onHook('before:save', async (data) => {
data.validated = true;
});
Subscribe to multiple hook events at once. Takes an array of IHook objects and an optional OnHookOptions object that is applied to each hook.
const hooks = [
{
event: 'before:myMethodWithHooks',
handler: async (data) => {
data.some = 'new data1';
},
},
{
event: 'after:myMethodWithHooks',
handler: async (data) => {
data.some = 'new data2';
},
},
];
myClass.onHooks(hooks);
// With options — insert all hooks at the top
myClass.onHooks(hooks, { position: 'Top' });
// With options — skip cloning for all hooks in this batch
myClass.onHooks(hooks, { useHookClone: false });
Subscribe to a hook event once. Takes an IHook object with event and handler properties. After the handler is called once, it is automatically removed.
myClass.onceHook({ event: 'before:myMethod2', handler: async (data) => {
data.some = 'new data';
}});
await myClass.hook('before:myMethod2', data); // handler runs once then is removed
console.log(myClass.hooks.size); // 0
Subscribe to a hook event before all other hooks. Takes an IHook object with event and handler properties. Returns the stored IHook (with generated id), or undefined if blocked by deprecation. Equivalent to calling onHook(hook, { position: "Top" }).
An optional PrependHookOptions object can be passed with:
useHookClone (boolean) — per-call override for hook cloning behaviormyClass.onHook({ event: 'before:myMethod2', handler: async (data) => {
data.some = 'new data';
}});
myClass.prependHook({ event: 'before:myMethod2', handler: async (data) => {
data.some = 'will run before new data';
}});
Subscribe to a hook event before all other hooks. Takes an IHook object with event and handler properties. After the handler is called once, it is automatically removed. Returns the stored IHook (with generated id), or undefined if blocked by deprecation.
An optional PrependHookOptions object can be passed with:
useHookClone (boolean) — per-call override for hook cloning behaviormyClass.onHook({ event: 'before:myMethod2', handler: async (data) => {
data.some = 'new data';
}});
myClass.prependOnceHook({ event: 'before:myMethod2', handler: async (data) => {
data.some = 'will run before new data';
}});
Removes all hooks for a specific event and returns the removed hooks as an IHook[] array. Returns an empty array if no hooks are registered for the event.
myClass.onHook({ event: 'before:myMethod2', handler: async (data) => {
data.some = 'new data';
}});
myClass.onHook({ event: 'before:myMethod2', handler: async (data) => {
data.some = 'more data';
}});
// Remove all hooks for a specific event
const removed = myClass.removeEventHooks('before:myMethod2');
console.log(removed.length); // 2
Unsubscribe a handler from a hook event. Takes an IHook object with event and handler properties. Returns the removed hook as an IHook object, or undefined if the handler was not found.
const handler = async (data) => {
data.some = 'new data';
};
myClass.onHook({ event: 'before:myMethod2', handler });
const removed = myClass.removeHook({ event: 'before:myMethod2', handler });
console.log(removed); // { event: 'before:myMethod2', handler: [Function] }
Remove one or more hooks by id, searching across all events. Accepts a single string or an array of string ids.
IHook, or undefined if not found.IHook[] array of the hooks that were successfully removed.When the last hook for an event is removed, the event key is cleaned up.
const myClass = new MyClass();
myClass.onHook({ id: 'hook-a', event: 'before:save', handler: async () => {} });
myClass.onHook({ id: 'hook-b', event: 'after:save', handler: async () => {} });
myClass.onHook({ id: 'hook-c', event: 'before:save', handler: async () => {} });
// Remove a single hook by id
const removed = myClass.removeHookById('hook-a');
console.log(removed?.id); // 'hook-a'
// Remove multiple hooks by ids
const removedMany = myClass.removeHookById(['hook-b', 'hook-c']);
console.log(removedMany.length); // 2
Unsubscribe from multiple hooks. Returns an array of the hooks that were successfully removed.
const hooks = [
{ event: 'before:save', handler: async (data) => { data.some = 'new data1'; } },
{ event: 'after:save', handler: async (data) => { data.some = 'new data2'; } },
];
myClass.onHooks(hooks);
const removed = myClass.removeHooks(hooks);
console.log(removed.length); // 2
All examples below assume the following setup unless otherwise noted:
import { Hookified } from 'hookified'; class MyClass extends Hookified { constructor(options) { super(options); } } const myClass = new MyClass();
If set to true, errors emitted as error will always be thrown, even if there are listeners. If set to false (default), errors will only be emitted to listeners.
const myClass = new MyClass({ throwOnEmitError: true });
myClass.on('error', (err) => {
console.log('listener received:', err.message);
});
try {
myClass.emit('error', new Error('This will throw despite having a listener'));
} catch (error) {
console.log(error.message); // This will throw despite having a listener
}
If set to true, errors will be thrown when emitting an error event with no listeners. This follows the standard Node.js EventEmitter behavior. Default is true.
const myClass = new MyClass({ throwOnEmptyListeners: true });
console.log(myClass.throwOnEmptyListeners); // true (default)
// This will throw because there are no error listeners
try {
myClass.emit('error', new Error('Something went wrong'));
} catch (error) {
console.log(error.message); // Something went wrong
}
// Add an error listener - now it won't throw
myClass.on('error', (error) => {
console.log('Error caught:', error.message);
});
myClass.emit('error', new Error('This will be caught')); // No throw, listener handles it
// You can also change it dynamically
myClass.throwOnEmptyListeners = false;
console.log(myClass.throwOnEmptyListeners); // false
Difference between throwOnEmitError and throwOnEmptyListeners:
throwOnEmitError: Throws when emitting 'error' event every time.throwOnEmptyListeners: Throws only when there are NO error listeners registeredWhen both are set to true, throwOnEmitError takes precedence.
Subscribe to an event.
myClass.on('message', (message) => {
console.log(message);
});
Unsubscribe from an event.
const handler = (message) => {
console.log(message);
};
myClass.on('message', handler);
myClass.off('message', handler);
Emit an event.
myClass.emit('message', 'Hello World');
Get all listeners for an event.
myClass.on('message', (message) => {
console.log(message);
});
console.log(myClass.listeners('message'));
Remove all listeners for an event.
myClass.on('message', (message) => {
console.log(message);
});
myClass.removeAllListeners('message');
Set the maximum number of listeners for a single event. Default is 0 (unlimited). Negative values are treated as 0. Setting to 0 disables the limit and the warning. When the limit is exceeded, a MaxListenersExceededWarning is emitted via console.warn but the listener is still added. This matches standard Node.js EventEmitter behavior.
myClass.setMaxListeners(1);
myClass.on('message', (message) => {
console.log(message);
});
myClass.on('message', (message) => {
console.log(message);
}); // warning emitted but listener is still added
console.log(myClass.listenerCount('message')); // 2
Subscribe to an event once.
myClass.once('message', (message) => {
console.log(message);
});
myClass.emit('message', 'Hello World'); // handler runs
myClass.emit('message', 'Hello World'); // handler does not run
Prepend a listener to an event. This will be called before any other listeners.
myClass.prependListener('message', (message) => {
console.log(message);
});
Prepend a listener to an event once. This will be called before any other listeners.
myClass.prependOnceListener('message', (message) => {
console.log(message);
});
myClass.emit('message', 'Hello World');
Get all event names.
myClass.on('message', (message) => {
console.log(message);
});
console.log(myClass.eventNames()); // ['message']
Get the count of listeners for an event or all events if eventName not provided.
myClass.on('message', (message) => {
console.log(message);
});
console.log(myClass.listenerCount('message')); // 1
Get all listeners for an event or all events if eventName not provided.
myClass.on('message', (message) => {
console.log(message);
});
console.log(myClass.rawListeners('message'));
Hookified integrates logging directly into the event system. When an eventLogger is configured, all emitted events are automatically logged to the appropriate log level based on the event name.
When you emit an event, Hookified automatically sends the event data to the configured eventLogger using the appropriate log method:
| Event Name | Logger Method |
|---|---|
error | eventLogger.error() |
warn | eventLogger.warn() |
debug | eventLogger.debug() |
trace | eventLogger.trace() |
fatal | eventLogger.fatal() |
| Any other | eventLogger.info() |
The logger receives two arguments:
{ event: eventName, data: originalData }Any logger that implements the Logger interface is compatible. This includes popular loggers like Pino, Winston, Bunyan, and others.
type Logger = {
trace: (message: string, ...args: unknown[]) => void;
debug: (message: string, ...args: unknown[]) => void;
info: (message: string, ...args: unknown[]) => void;
warn: (message: string, ...args: unknown[]) => void;
error: (message: string, ...args: unknown[]) => void;
fatal: (message: string, ...args: unknown[]) => void;
};
import { Hookified } from 'hookified';
import pino from 'pino';
const logger = pino();
class MyService extends Hookified {
constructor() {
super({ eventLogger: logger });
}
async processData(data) {
// This will log to logger.info with the data
this.emit('info', { action: 'processing', data });
try {
// ... process data
this.emit('debug', { action: 'completed', result: 'success' });
} catch (err) {
// This will log to logger.error with the error message
this.emit('error', err);
}
}
}
const service = new MyService();
// All events are automatically logged
service.emit('info', 'Service started'); // -> logger.info()
service.emit('warn', { message: 'Low memory' }); // -> logger.warn()
service.emit('error', new Error('Failed')); // -> logger.error()
service.emit('custom-event', { foo: 'bar' }); // -> logger.info() (default)
You can also set or change the eventLogger after instantiation:
const service = new MyService();
service.eventLogger = pino({ level: 'debug' });
// Or remove the eventLogger
service.eventLogger = undefined;
We are doing very simple benchmarking to see how this compares to other libraries using tinybench. This is not a full benchmark but just a simple way to see how it performs.
| name | summary | ops/sec | time/op | margin | samples |
|---|---|---|---|---|---|
| Hookified (v2.0.1) | 🥇 | 5M | 221ns | ±0.01% | 5M |
| Hookable (v6.0.1) | -59% | 2M | 569ns | ±0.01% | 2M |
This shows how on par hookified is to the native EventEmitter and popular eventemitter3. These are simple emitting benchmarks to see how it performs. Our goal is to be as close or better than the other libraries including native (EventEmitter).
| name | summary | ops/sec | time/op | margin | samples |
|---|---|---|---|---|---|
| Hookified (v2.1.0) | 🥇 | 17M | 73ns | ±0.02% | 14M |
| EventEmitter3 (v5.0.4) | -2.2% | 17M | 70ns | ±0.02% | 14M |
| EventEmitter (v24.14.0) | -4.5% | 16M | 70ns | ±0.02% | 14M |
| Emittery (v2.0.0) | -92% | 1M | 792ns | ±0.01% | 1M |
Note: the EventEmitter version is Nodejs versioning.
v2 overhauls hook storage to use IHook objects instead of raw functions. This enables hook IDs, ordering via position, cloning control, and new hook types like WaterfallHook. onHook now supports both the v1 positional (event, handler) form and the new IHook object form, so this is not a breaking change:
// v1 style — still works
hookified.onHook('before:save', async (data) => {});
// v2 style — IHook object with options support
hookified.onHook({ event: 'before:save', handler: async (data) => {} });
// addHook also works as an alias for the positional form
hookified.addHook('before:save', async (data) => {});
Other common changes:
| v1 | v2 |
|---|---|
throwHookErrors | throwOnHookError |
logger | eventLogger |
onHookEntry(hook) | onHook(hook) |
HookEntry type | IHook interface |
Hook type (fn) | HookFn type |
getHooks() returns HookFn[] | getHooks() returns IHook[] |
removeHook(event, handler) | removeHook({ event, handler }) |
See below for full details on each change.
throwHookErrors removed — use throwOnHookError insteadthrowOnEmptyListeners now defaults to truelogger renamed to eventLoggermaxListeners default changed from 100 to 0 (unlimited) and no longer truncatesonHookEntry removed — use onHook insteadonHook signature updated (not breaking)HookEntry type and Hook type removedremoveHook and removeHooks now return removed hooksremoveHook, removeHooks, and getHooks no longer check for deprecated hooksIHook objectsonceHook, prependHook, prependOnceHook, and removeHook now take IHookonHook now returns the stored hookHook class now availableWaterfallHook class for sequential data transformation pipelinesuseHookClone optiononHook now accepts OnHookOptionsIHook now has an id propertyremoveEventHooks method| Change | Summary |
|---|---|
throwHookErrors | Renamed to throwOnHookError |
throwOnEmptyListeners | Default changed from false to true |
logger | Renamed to eventLogger |
maxListeners | Default changed from 100 to 0 (unlimited), no longer truncates |
onHookEntry | Removed — use onHook instead |
onHook signature | Now takes IHook object or (event, handler) — both supported (not breaking) |
HookEntry / Hook types | Replaced with IHook / HookFn |
removeHook / removeHooks | Now return removed hooks; no longer check deprecated status |
| Internal hook storage | Uses IHook objects instead of raw functions |
onceHook, prependHook, etc. | Now take IHook instead of (event, handler) |
onHook return | Now returns stored IHook (was void) |
throwHookErrors removed — use throwOnHookError insteadThe deprecated throwHookErrors option and property has been removed. Use throwOnHookError instead.
Before (v1):
super({ throwHookErrors: true });
myClass.throwHookErrors = false;
After (v2):
super({ throwOnHookError: true });
myClass.throwOnHookError = false;
throwOnEmptyListeners now defaults to trueThe throwOnEmptyListeners option now defaults to true, matching standard Node.js EventEmitter behavior. Previously it defaulted to false. If you emit an error event with no listeners registered, an error will now be thrown by default.
Before (v1):
const myClass = new MyClass(); // throwOnEmptyListeners defaults to false
myClass.emit('error', new Error('No throw')); // silently ignored
After (v2):
const myClass = new MyClass(); // throwOnEmptyListeners defaults to true
myClass.emit('error', new Error('This will throw')); // throws!
// To restore v1 behavior:
const myClass2 = new MyClass({ throwOnEmptyListeners: false });
logger renamed to eventLoggerThe logger option and property has been renamed to eventLogger to avoid conflicts with other logger properties in your classes.
Before (v1):
super({ logger });
myClass.logger = pino({ level: 'debug' });
After (v2):
super({ eventLogger: logger });
myClass.eventLogger = pino({ level: 'debug' });
maxListeners default changed from 100 to 0 (unlimited) and no longer truncatesThe default maximum number of listeners has changed from 100 to 0 (unlimited). The MaxListenersExceededWarning will no longer be emitted unless you explicitly set a limit via setMaxListeners(). Additionally, setMaxListeners() no longer truncates existing listeners — it only sets the warning threshold, matching standard Node.js EventEmitter behavior.
Before (v1):
const myClass = new MyClass(); // maxListeners defaults to 100
// Warning emitted after adding 100+ listeners to the same event
// setMaxListeners() would truncate existing listeners exceeding the limit
After (v2):
const myClass = new MyClass(); // maxListeners defaults to 0 (unlimited)
// No warning — unlimited listeners allowed
// setMaxListeners() only sets warning threshold, never removes listeners
// To restore v1 warning behavior:
myClass.setMaxListeners(100);
onHookEntry removed — use onHook insteadThe onHookEntry method has been removed. Use onHook which now accepts an IHook object (or array of IHook) directly.
Before (v1):
hookified.onHookEntry({ event: 'before:save', handler: async (data) => {} });
After (v2):
hookified.onHook({ event: 'before:save', handler: async (data) => {} });
onHook signature updatedonHook now supports both the v1 positional (event, handler) form and the new IHook object form. This is not a breaking change — existing v1 code continues to work. The IHook object form is recommended for new code as it supports hook IDs, positioning, and cloning options. You can also use addHook(event, handler) as an alias or onHooks() for bulk registration.
// v1 style — still works
hookified.onHook('before:save', async (data) => {});
// v2 style — IHook object with full options support
hookified.onHook({ event: 'before:save', handler: async (data) => {} });
// For multiple hooks, use onHooks
hookified.onHooks([
{ event: 'before:save', handler: async (data) => {} },
{ event: 'after:save', handler: async (data) => {} },
]);
// addHook also works as an alias for positional args
hookified.addHook('before:save', async (data) => {});
HookEntry type and Hook type removedThe HookEntry type has been removed and replaced with the IHook interface. The Hook type (function type) has been renamed to HookFn.
Before (v1):
import type { HookEntry, Hook } from 'hookified';
const hook: HookEntry = { event: 'before:save', handler: async () => {} };
const myHook: Hook = async (data) => {};
After (v2):
import type { IHook, HookFn } from 'hookified';
const hook: IHook = { event: 'before:save', handler: async () => {} };
const myHook: HookFn = async (data) => {};
removeHook and removeHooks now return removed hooksremoveHook now returns the removed hook as an IHook object (or undefined if not found). removeHooks now returns an IHook[] array of the hooks that were successfully removed. Previously both returned void.
Before (v1):
hookified.removeHook('before:save', handler); // void
hookified.removeHooks(hooks); // void
After (v2):
const removed = hookified.removeHook({ event: 'before:save', handler }); // IHook | undefined
const removedHooks = hookified.removeHooks(hooks); // IHook[]
removeHook, removeHooks, and getHooks no longer check for deprecated hooksPreviously, removeHook, removeHooks, and getHooks would skip their operation and emit a deprecation warning when called with a deprecated hook name and allowDeprecated was false. This made it impossible to clean up or inspect deprecated hooks. These methods now always operate regardless of deprecation status.
IHook objectsThe internal _hooks map now stores full IHook objects (Map<string, IHook[]>) instead of raw handler functions (Map<string, HookFn[]>). This means .hooks returns Map<string, IHook[]> and .getHooks() returns IHook[] | undefined.
Before (v1):
const hooks = myClass.getHooks('before:save'); // HookFn[]
hooks[0](data); // direct function call
After (v2):
const hooks = myClass.getHooks('before:save'); // IHook[]
hooks[0].handler(data); // access .handler property
hooks[0].event; // 'before:save'
onceHook, prependHook, prependOnceHook, and removeHook now take IHookThese methods now accept an IHook object instead of separate (event, handler) arguments.
Before (v1):
hookified.onceHook('before:save', async (data) => {});
hookified.prependHook('before:save', async (data) => {});
hookified.prependOnceHook('before:save', async (data) => {});
hookified.removeHook('before:save', handler);
After (v2):
hookified.onceHook({ event: 'before:save', handler: async (data) => {} });
hookified.prependHook({ event: 'before:save', handler: async (data) => {} });
hookified.prependOnceHook({ event: 'before:save', handler: async (data) => {} });
hookified.removeHook({ event: 'before:save', handler });
onHook now returns the stored hookonHook now returns the stored IHook object (or undefined if blocked by deprecation). Previously it returned void. The returned reference is the exact object stored internally, making it easy to later remove with removeHook().
Before (v1):
hookified.onHook({ event: 'before:save', handler }); // void
After (v2):
const stored = hookified.onHook({ event: 'before:save', handler }); // IHook | undefined
hookified.removeHook(stored); // exact reference match
Hook classA new Hook class is available for creating hook entries. It implements the IHook interface and can be used anywhere IHook is accepted.
import { Hook } from 'hookified';
const hook = new Hook('before:save', async (data) => {
data.validated = true;
});
myClass.onHook(hook);
WaterfallHook classA new WaterfallHook class is available for creating sequential data transformation pipelines. It implements the IHook interface and integrates directly with Hookified.onHook(). Each hook in the chain receives a WaterfallHookContext with initialArgs (the original arguments) and results (an array of { hook, result } entries from all previous hooks).
import { Hookified, WaterfallHook } from 'hookified';
class MyClass extends Hookified {
constructor() { super(); }
}
const myClass = new MyClass();
const wh = new WaterfallHook('save', ({ results }) => {
const data = results[results.length - 1].result;
console.log('Saved:', data);
});
wh.addHook(({ initialArgs }) => {
return { ...initialArgs, validated: true };
});
wh.addHook(({ results }) => {
return { ...results[results.length - 1].result, timestamp: Date.now() };
});
myClass.onHook(wh);
await myClass.hook('save', { name: 'test' });
// Saved: { name: 'test', validated: true, timestamp: ... }
See the Waterfall Hook section for full documentation.
useHookClone optionA new useHookClone option (default true) controls whether hook objects are shallow-cloned before storing. When enabled, external mutation of a registered hook object won't affect the internal state. Set to false to store the original reference for performance or when you need reference equality.
class MyClass extends Hookified {
constructor() { super({ useHookClone: false }); }
}
onHook now accepts OnHookOptionsonHook now accepts an optional second parameter of type OnHookOptions. This allows you to override the instance-level useHookClone setting and control hook positioning on a per-call basis.
// Override useHookClone for this specific call
hookified.onHook({ event: 'before:save', handler }, { useHookClone: false });
// Insert at the top of the handlers array instead of the end
hookified.onHook({ event: 'before:save', handler }, { position: 'Top' });
// Insert at a specific index
hookified.onHook({ event: 'before:save', handler }, { position: 1 });
IHook now has an id propertyEvery hook now has an optional id property. If not provided, a UUID is auto-generated via crypto.randomUUID(). The id enables easier lookups and removal via the new getHook(id) and removeHookById(id) methods, which search across all events.
Registering a hook with the same id on the same event replaces the existing hook in-place (preserving its position).
// With custom id
const stored = hookified.onHook({
id: 'my-validation',
event: 'before:save',
handler: async (data) => { data.validated = true; },
});
// Without id — auto-generated
const stored2 = hookified.onHook({
event: 'before:save',
handler: async (data) => {},
});
console.log(stored2.id); // e.g. '550e8400-e29b-41d4-a716-446655440000'
// Look up by id (searches all events)
const hook = hookified.getHook('my-validation');
// Remove by id (searches all events)
hookified.removeHookById('my-validation');
// Remove multiple by ids
hookified.removeHookById(['hook-a', 'hook-b']);
The Hook class also accepts an optional id parameter:
const hook = new Hook('before:save', handler, 'my-custom-id');
removeEventHooks methodA new removeEventHooks(event) method removes all hooks for a specific event and returns the removed hooks as an IHook[] array.
const removed = hookified.removeEventHooks('before:save');
console.log(removed.length); // number of hooks removed
Hookified is written in TypeScript and tests are written with vitest. To setup the environment and run the tests:
pnpm i && pnpm test
Note that we are using pnpm as our package manager. If you don't have it installed, you can install it globally with:
npm install -g pnpm
To contribute follow the Contributing Guidelines and Code of Conduct.
FAQs
Event Emitting and Middleware Hooks
The npm package hookified receives a total of 7,870,639 weekly downloads. As such, hookified popularity was classified as popular.
We found that hookified demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 1 open source maintainer collaborating on the project.
Did you know?
Socket for GitHub automatically highlights issues in each pull request and monitors the health of all your open source dependencies. Discover the contents of your packages and block harmful activity before you install or update your dependencies.
Research
/Security News
Socket is tracking cloned Open VSX extensions tied to GlassWorm, with several updated from benign-looking sleepers into malware delivery vehicles.
Product
Reachability analysis for PHP is now available in experimental, helping teams identify which vulnerabilities are actually exploitable.
Product
Export Socket alert data to your own cloud storage in JSON, CSV, or Parquet, with flexible snapshot or incremental delivery.