pending-value

A thin abstraction over promises that makes them retargetable, so that you can represent a single value that may be asynchronously computed and re-computed.

Installation

$ npm install @f/pending-value

Usage

You should use pendingValue when you have a thing that may be recomputed or rebuilt over time, but you want to abstract that fact away from the code that uses it. For instance, watching a browserify bundle:

var pendingValue = require('@f/pending-value')
var browserify = require('browserify')
var concat = require('concat-stream')
var watchify = require('watchify')
var route = require('koa-route')
var fs = require('fs')

var js = pendingValue()
var b = browserify({
  entries: 'entry.js',
  cache: {},
  packageCache: {},
  plugin: [watchify]
})

b.on('update', bundle)
bundle()

function bundle() {
  js.pending()
  b.bundle().pipe(concat(str = js.ready(str))
}

app.use(route.get('/bundle.js', function *() {
  this.body = yield js.value()
})

API

pendingValue()

Returns: An object with three methods. pending(), ready(value), and value(). pending() puts the structure back into its loading state, blocking all requests for value until ready is called with a new value.

License

MIT