Skip to main content

Documentation Index

Fetch the complete documentation index at: https://mintlify.com/visible/cruel/llms.txt

Use this file to discover all available pages before exploring further.

​
cruel()

Wraps a function with chaos behavior. 
function cruel<T extends AnyFn>(fn: T, options: ChaosOptions = {}): T
​
fn
T extends AnyFn
required
The function to wrap with chaos behavior
​
options
ChaosOptions
Chaos configuration options
Returns: T - Wrapped function with chaos behavior

​
Example

import { cruel } from '@cruel/cruel'

const fetchUser = cruel(async (id: string) => {
  return db.users.findById(id)
}, { fail: 0.1, delay: [100, 500] })

​
cruel.fail()

Wraps a function to fail at a specific rate. 
function fail<T extends AnyFn>(fn: T, rate = 0.1): T
​
fn
T extends AnyFn
required
The function to wrap
​
rate
number
default:"0.1"
Failure rate (0-1). Default is 0.1 (10%)
Returns: T - Function that fails randomly at the specified rate

​
Example

import { cruel } from '@cruel/cruel'

const unreliableApi = cruel.fail(async () => {
  return fetch('/api/data')
}, 0.2) // Fails 20% of the time

​
cruel.slow()

Wraps a function to add artificial delay. 
function slow<T extends AnyFn>(fn: T, delay: number | [number, number] = 500): T
​
fn
T extends AnyFn
required
The function to wrap
​
delay
number | [number, number]
default:"500"
Delay in milliseconds, or range [min, max] for random delay
Returns: T - Function with added delay

​
Example

import { cruel } from '@cruel/cruel'

const slowQuery = cruel.slow(async (query: string) => {
  return db.execute(query)
}, [1000, 3000]) // Random delay between 1-3 seconds

​
cruel.timeout()

Wraps a function to timeout at a specific rate. 
function timeout<T extends AnyFn>(fn: T, rate = 0.1): T
​
fn
T extends AnyFn
required
The function to wrap
​
rate
number
default:"0.1"
Timeout rate (0-1). Default is 0.1 (10%)
Returns: T - Function that times out randomly at the specified rate

​
Example

import { cruel } from '@cruel/cruel'

const timeoutProne = cruel.timeout(async () => {
  return longRunningOperation()
}, 0.15) // Times out 15% of the time

​
cruel.flaky()

Wraps a function with flaky behavior (combination of failures, timeouts, and delays). 
function flaky<T extends AnyFn>(fn: T, intensity = 0.2): T
​
fn
T extends AnyFn
required
The function to wrap
​
intensity
number
default:"0.2"
Flakiness intensity (0-1). Higher values mean more chaos
Returns: T - Flaky function with combined chaos behaviors Behavior: Applies chaos with:
  • fail: intensity * 0.5
  • timeout: intensity * 0.25
  • delay: [100, 1000]

​
Example

import { cruel } from '@cruel/cruel'

const flakyService = cruel.flaky(async () => {
  return externalAPI.getData()
}, 0.3) // 30% intensity

​
cruel.unreliable()

Wraps a function with high unreliability (failures, timeouts, delays, jitter). 
function unreliable<T extends AnyFn>(fn: T): T
​
fn
T extends AnyFn
required
The function to wrap
Returns: T - Highly unreliable function Behavior: Applies chaos with:
  • fail: 0.3
  • timeout: 0.1
  • delay: [200, 2000]
  • jitter: 500

​
Example

import { cruel } from '@cruel/cruel'

const unreliableDB = cruel.unreliable(async (query: string) => {
  return database.query(query)
})

​
cruel.nightmare()

Wraps a function with extreme chaos for stress testing. 
function nightmare<T extends AnyFn>(fn: T): T
​
fn
T extends AnyFn
required
The function to wrap
Returns: T - Function with extreme chaos behavior Behavior: Applies chaos with:
  • fail: 0.5
  • timeout: 0.2
  • delay: [500, 5000]
  • jitter: 1000

​
Example

import { cruel } from '@cruel/cruel'

const worstCase = cruel.nightmare(async () => {
  return criticalOperation()
})

Build docs developers (and LLMs) love

Get started for freeTalk to us