For J V

request_with_timeout.js

export function request (url, params = {}) {
  return fetch(url, params)
  .then(res => res && res.json())
}

export function withTimeout (timeout, fn, context) {
  return (...args) => {
    return new Promise((resolve, reject) => {
      setTimeout(() => reject(new Error('Function timeout')), timeout)
      const res = fn.apply(context, args)
      
      if (!res.then)  return resolve(res)
      return res.then(resolve, reject)
    })
  }
}

export const requestWithTimeout = withTimeout(2000, request)

export const apiFactory = (requestWithTimeout) => ({
  doSomething: () =>  requestWithTimeout('https://YOUR_DOMAIN/api/SOME_END_POINT')
                      .then(
                        data => 'do something here',
                        e => console.error(e.stack)
                       )
})

export const detailLogicFactory = (api) => {
  playWithDoSomething: () => {
    api.doSomething().then(data => {
      'end user logic here'
    })
  }
}

spec_request_with_timeout.js

import { detailLogicFactory } from './request_with_timeout'

describe('detailLogic', () => {  
  it('success', (done) => {
    const detailLogic = detailLogicFactory({
      doSomething: () => Promise.resolve('correct result') 
    })
    
    detailLogic.playWithDoSomething().then(res => {
      expect(res).to.eql('correct result')
      done()
    })
  })
  
  it('timeout', (done) => {
    const detailLogic = detailLogicFactory({
      doSomething: () => new Promise(resolve => setTimeout(resolve, 10000))
    })
    
    detailLogic.playWithDoSomething().catch(e => {
      expect(e.message).to.eql('Function timeout')
      done()
    })
  })
})