thunk-loop v1.0.7

thunk-loop

Asynchronous tasks loop (while (true) { ... }).

thunks

Demo

Infinite Clock:

const thunk = require('thunks')()
const thunkLoop = require('..')

var i = 0
thunkLoop(function *() {
  yield thunk.delay(1000)
  i = ++i % 60
  console.log(i)
  return true
})(function (_) {
  // will never reach here.
})

API

const thunkLoop = require('thunk-loop')

thunkLoop(iter, errorHandle)

return thunk function. You should run the thunk function because of thunk's lazy evaluation. If iter is infinite, you will not get the last result except error occured.

• iter: {Function}, it is your task loop, can be sync or async task. If iter's result is true, the loop will continue, otherwise the loop will terminate.

  Sync function:

  var i = 1000
  thunkLoop(function () {
    if (--i) return true
    return 'OK'
  })(function (err, res) {
    console.log(err, res, i) // null, 'OK', 0
  })

  Promise:

  var i = 1000
  thunkLoop(function () {
    if (--i) return Promise.resolve(true)
    return Promise.resolve('OK')
  })(function (err, res) {
    console.log(err, res, i) // null, 'OK', 0
  })

  Generator function:

  var i = 1000
  thunkLoop(function *() {
    // yield thunk or promise
    if (--i) return yield thunk(true)
    return yield Promise.resolve('OK')
  })(function (err, res) {
    console.log(err, res, i) // null, 'OK', 0
  })

• errorHandle: {Function}, it is optional, can be sync or async function. It is used to catch the exception from iter.

  If errorHandle omit. the exception from iter will terminate loop:

  thunkLoop(function *() {
    throw new Error('error!')
  })(function (err, res) {
    console.log(err.message, ) 'error!'
  })

  If errorHandle return true. the exception from iter will ignore and loop will continue:

  var i = 1000
  thunkLoop(function () {
    if (--i) throw new Error('test')
    return 'OK'
  }, function (err) {
    console.log(err.message) // 'test'
    return true
  })(function (err, res) {
    console.log(err, res, i) // null, 'OK', 0
  })

  If errorHandle throw error:

  var i = 1000
  thunkLoop(function () {
    if (--i) throw new Error('test')
    return 'OK'
  }, function (err) {
    console.log(err.message) // 'test'
    throw new Error('errorHandle error')
  })(function (err, res) {
    console.log(err.message, i) // 'errorHandle error', 999
  })