throttle

Creates a throttled function that limits invocations to a specified interval

Usage

The throttle function creates a new function that, when called, will only execute the original function at most once per specified time interval. This is useful for limiting the rate at which a function can fire, especially for performance-intensive operations like handling scroll or resize events.

The function accepts two parameters:

An options object with:
- interval: The minimum time (in milliseconds) between function invocations
- trailing (optional): If true, also calls the function after the throttle period if it was invoked during the throttle
The function to be throttled

The returned throttled function also includes these methods:

isThrottled(): boolean: To check if there’s currently an active throttle
trigger(...args): void: To invoke the wrapped function without waiting for the next interval

import * as 
import _
_ from 'radashi'

// Throttle a scroll event handler
const 
const handleScroll: () => void
handleScroll = () => {
  
var console: Console
The console module provides a simple debugging console that is similar to the
JavaScript console mechanism provided by web browsers.
The module exports two specific components:

A Console class with methods such as console.log(), console.error() and console.warn() that can be used to write to any Node.js stream.
A global console instance configured to write to process.stdout and
process.stderr. The global console can be used without importing the node:console module.

Warning: The global console object's methods are neither consistently
synchronous like the browser APIs they resemble, nor are they consistently
asynchronous like all other Node.js streams. See the note on process I/O for
more information.
Example using the global console:
console.log('hello world');
// Prints: hello world, to stdout
console.log('hello %s', 'world');
// Prints: hello world, to stdout
console.error(new Error('Whoops, something bad happened'));
// Prints error message and stack trace to stderr:
//   Error: Whoops, something bad happened
//     at [eval]:5:15
//     at Script.runInThisContext (node:vm:132:18)
//     at Object.runInThisContext (node:vm:309:38)
//     at node:internal/process/execution:77:19
//     at [eval]-wrapper:6:22
//     at evalScript (node:internal/process/execution:76:60)
//     at node:internal/main/eval_string:23:3

const name = 'Will Robinson';
console.warn(`Danger ${name}! Danger!`);
// Prints: Danger Will Robinson! Danger!, to stderr
Example using the Console class:
const out = getStreamSomehow();
const err = getStreamSomehow();
const myConsole = new console.Console(out, err);

myConsole.log('hello world');
// Prints: hello world, to out
myConsole.log('hello %s', 'world');
// Prints: hello world, to out
myConsole.error(new Error('Whoops, something bad happened'));
// Prints: [Error: Whoops, something bad happened], to err

const name = 'Will Robinson';
myConsole.warn(`Danger ${name}! Danger!`);
// Prints: Danger Will Robinson! Danger!, to err
@see ― source
console.
Console.log(message?: any, ...optionalParams: any[]): void (+1 overload)
Prints to stdout with newline. Multiple arguments can be passed, with the
first used as the primary message and all additional used as substitution
values similar to printf(3)
(the arguments are all passed to util.format()).
const count = 5;
console.log('count: %d', count);
// Prints: count: 5, to stdout
console.log('count:', count);
// Prints: count: 5, to stdout
See util.format() for more information.
@since ― v0.1.100
log('Scroll position:', 
var window: Window & typeof globalThis
MDN Reference
window.
scrollY: number
MDN Reference
scrollY)
}
const 
const throttledScroll: _.ThrottledFunction<[]>
throttledScroll = 
import _
_.
function throttle<[]>({ interval, trailing }: {
    interval: number;
    trailing?: boolean;
}, func: () => any): _.ThrottledFunction<[]>
Given an interval and a function returns a new function that will
only call the source function if interval milliseconds have passed
since the last invocation.
@see ― https://radashi.js.org/reference/curry/throttle
@example 
const sup = throttle({ interval: 1000 }, () => {
  console.log("sup")
})
sup() // => logs "sup"
sup() // => no logs
setTimeout(() => sup(), 500) // => no logs
setTimeout(() => sup(), 1000) // => logs "sup"
@version ― 12.1.0
throttle({ 
interval: number
interval: 200 }, 
const handleScroll: () => void
handleScroll)
var window: Window & typeof globalThis
MDN Reference
window.
addEventListener<"scroll">(type: "scroll", listener: (this: Window, ev: Event) => any, options?: boolean | AddEventListenerOptions): void (+1 overload)
Appends an event listener for events whose type attribute value is type. The callback argument sets the callback that will be invoked when the event is dispatched.
The options argument sets listener-specific options. For compatibility this can be a boolean, in which case the method behaves exactly as if the value was specified as options's capture.
When set to true, options's capture prevents callback from being invoked when the event's eventPhase attribute value is BUBBLING_PHASE. When false (or not present), callback will not be invoked when event's eventPhase attribute value is CAPTURING_PHASE. Either way, callback will be invoked if event's eventPhase attribute value is AT_TARGET.
When set to true, options's passive indicates that the callback will not cancel the event by invoking preventDefault(). This is used to enable performance optimizations described in § 2.8 Observing event listeners.
When set to true, options's once indicates that the callback will only be invoked once after which the event listener will be removed.
If an AbortSignal is passed for options's signal, then the event listener will be removed when signal is aborted.
The event listener is appended to target's event listener list and is not appended if it has the same type, callback, and capture.
MDN Reference
addEventListener('scroll', 
const throttledScroll: _.ThrottledFunction<[]>
throttledScroll)

// Throttle an API call
const 
const throttledFetch: _.ThrottledFunction<[]>
throttledFetch = 
import _
_.
function throttle<[]>({ interval, trailing }: {
    interval: number;
    trailing?: boolean;
}, func: () => any): _.ThrottledFunction<[]>
Given an interval and a function returns a new function that will
only call the source function if interval milliseconds have passed
since the last invocation.
@see ― https://radashi.js.org/reference/curry/throttle
@example 
const sup = throttle({ interval: 1000 }, () => {
  console.log("sup")
})
sup() // => logs "sup"
sup() // => no logs
setTimeout(() => sup(), 500) // => no logs
setTimeout(() => sup(), 1000) // => logs "sup"
@version ― 12.1.0
throttle(
  { 
interval: number
interval: 5000, 
trailing?: boolean
trailing: true },
  async () => {
    const 
const response: Response
response = await 
function fetch(input: string | URL | globalThis.Request, init?: RequestInit): Promise<Response> (+1 overload)
MDN Reference
fetch('https://api.example.com/data')
    const 
const data: any
data = await 
const response: Response
response.
Body.json(): Promise<any>
MDN Reference
json()
    
var console: Console
The console module provides a simple debugging console that is similar to the
JavaScript console mechanism provided by web browsers.
The module exports two specific components:

A Console class with methods such as console.log(), console.error() and console.warn() that can be used to write to any Node.js stream.
A global console instance configured to write to process.stdout and
process.stderr. The global console can be used without importing the node:console module.

Warning: The global console object's methods are neither consistently
synchronous like the browser APIs they resemble, nor are they consistently
asynchronous like all other Node.js streams. See the note on process I/O for
more information.
Example using the global console:
console.log('hello world');
// Prints: hello world, to stdout
console.log('hello %s', 'world');
// Prints: hello world, to stdout
console.error(new Error('Whoops, something bad happened'));
// Prints error message and stack trace to stderr:
//   Error: Whoops, something bad happened
//     at [eval]:5:15
//     at Script.runInThisContext (node:vm:132:18)
//     at Object.runInThisContext (node:vm:309:38)
//     at node:internal/process/execution:77:19
//     at [eval]-wrapper:6:22
//     at evalScript (node:internal/process/execution:76:60)
//     at node:internal/main/eval_string:23:3

const name = 'Will Robinson';
console.warn(`Danger ${name}! Danger!`);
// Prints: Danger Will Robinson! Danger!, to stderr
Example using the Console class:
const out = getStreamSomehow();
const err = getStreamSomehow();
const myConsole = new console.Console(out, err);

myConsole.log('hello world');
// Prints: hello world, to out
myConsole.log('hello %s', 'world');
// Prints: hello world, to out
myConsole.error(new Error('Whoops, something bad happened'));
// Prints: [Error: Whoops, something bad happened], to err

const name = 'Will Robinson';
myConsole.warn(`Danger ${name}! Danger!`);
// Prints: Danger Will Robinson! Danger!, to err
@see ― source
console.
Console.log(message?: any, ...optionalParams: any[]): void (+1 overload)
Prints to stdout with newline. Multiple arguments can be passed, with the
first used as the primary message and all additional used as substitution
values similar to printf(3)
(the arguments are all passed to util.format()).
const count = 5;
console.log('count: %d', count);
// Prints: count: 5, to stdout
console.log('count:', count);
// Prints: count: 5, to stdout
See util.format() for more information.
@since ― v0.1.100
log(
const data: any
data)
  },
)

// Check if throttled
var console: Console
The console module provides a simple debugging console that is similar to the
JavaScript console mechanism provided by web browsers.
The module exports two specific components:

A Console class with methods such as console.log(), console.error() and console.warn() that can be used to write to any Node.js stream.
A global console instance configured to write to process.stdout and
process.stderr. The global console can be used without importing the node:console module.

Warning: The global console object's methods are neither consistently
synchronous like the browser APIs they resemble, nor are they consistently
asynchronous like all other Node.js streams. See the note on process I/O for
more information.
Example using the global console:
console.log('hello world');
// Prints: hello world, to stdout
console.log('hello %s', 'world');
// Prints: hello world, to stdout
console.error(new Error('Whoops, something bad happened'));
// Prints error message and stack trace to stderr:
//   Error: Whoops, something bad happened
//     at [eval]:5:15
//     at Script.runInThisContext (node:vm:132:18)
//     at Object.runInThisContext (node:vm:309:38)
//     at node:internal/process/execution:77:19
//     at [eval]-wrapper:6:22
//     at evalScript (node:internal/process/execution:76:60)
//     at node:internal/main/eval_string:23:3

const name = 'Will Robinson';
console.warn(`Danger ${name}! Danger!`);
// Prints: Danger Will Robinson! Danger!, to stderr
Example using the Console class:
const out = getStreamSomehow();
const err = getStreamSomehow();
const myConsole = new console.Console(out, err);

myConsole.log('hello world');
// Prints: hello world, to out
myConsole.log('hello %s', 'world');
// Prints: hello world, to out
myConsole.error(new Error('Whoops, something bad happened'));
// Prints: [Error: Whoops, something bad happened], to err

const name = 'Will Robinson';
myConsole.warn(`Danger ${name}! Danger!`);
// Prints: Danger Will Robinson! Danger!, to err
@see ― source
console.
Console.log(message?: any, ...optionalParams: any[]): void (+1 overload)
Prints to stdout with newline. Multiple arguments can be passed, with the
first used as the primary message and all additional used as substitution
values similar to printf(3)
(the arguments are all passed to util.format()).
const count = 5;
console.log('count: %d', count);
// Prints: count: 5, to stdout
console.log('count:', count);
// Prints: count: 5, to stdout
See util.format() for more information.
@since ― v0.1.100
log('Is throttled:', 
const throttledFetch: _.ThrottledFunction<[]>
throttledFetch.
function isThrottled(): boolean
Checks if there is any invocation throttled
isThrottled())

Timing

A visual representation of the throttle behavior when interval is set to 200ms:

Time: 0ms - - - - 100ms - - - - 200ms - - - - 300ms - - - - 400ms - - - -
Throttle Invocations: x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x - - -
Source Invocations: x - - - - - - - - - - - - x - - - - - - - - - - - - - x - - - - - -

When the trailing option is set to true, an additional invocation occurs after the throttle period if any calls were made during the throttled time:

Time: 0ms - - - - 100ms - - - - 200ms - - - - 300ms - - - - 400ms - - - -
Throttle Invocations: x x x x x x x x x x x x x x x x x x x x x - - - - - - - - - - - - -
Source Invocations: x - - - - - - - - - - - - x - - - - - - - - - - - - - x - - - - - -

In this diagram, ‘x’ represents function invocations, and ’-’ represents time passing.