[Compose] 10. Capture Side Effects in a Task

We examine the data structure Task, see some constructors, familiar methods, and finally how it captures side effects through laziness.

We using a 'data.task' library. It is a bit similar to $q library in Angular. Accepts one function, function takes two params, 'reject function' & 'resolve function'.

import Task from 'data.task';

const launchMissiles = () =>

  new Task((rej, res) => {

    console.log('launch missiles!')

    res('missile')

  })

Because this is laziness, therefore, we can compose logic based on that:

const app = launchMissiles().map(x => x + '!')

app

.map(x => x + '!')

.fork(e => console.error('err', e),

      x => console.log('success', x))

If inside 'lauchMissiles' call 'reject' function, all the map function chaining on app won't be called anymore.

'fork' is the actually function which trigger it works.

-----

import Task from 'data.task';

const launchMissiles = () =>

  new Task((rej, res) => {

    console.log('launch missiles!')

    res('missile')

  })

const app = launchMissiles().map(x => x + '!')

app

.map(x => x + '!')

.fork(e => console.error('err', e),

      x => console.log('success', x))

//launch missiles!

success

巴特西

[Compose] 10. Capture Side Effects in a Task

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