letta-value

Extends letta to accept and handles more than functions only. Handles all kind of results from letta. Basically, creating promise from everything - strings, arrays, objects, functions, generators, generator functions, promises, streams, child processes, observables, maps, symbols, dates and etc.

Install

npm i letta-value --save

Usage

For more use-cases see the tests

• [val] {Mixed} believe me, everything
• return {Promise}

Example

const lettaValue = require('letta-value')

// strings
lettaValue('foo bar').then(res => {
  console.log(res) // => 'foo bar'
})

// numbers
lettaValue(123).then(res => {
  console.log(res) // => 123
})

// errors
lettaValue(new Error('foo err'))
.catch(err => {
  console.error(err.message) // => 'foo err'
})

// functions
lettaValue(function noopFn () {})
.then(res => {
  // res is the noop function
  // it won't be executed or anything
  console.log(res.name) // => 'noopFn'
}, console.error)

Extended examples

Meant to be used with letta, because letta accepts only function type.
The following is always-done package, which is completely built on top of letta and letta-value

var letta = require('letta')
var lettaValue = require('letta-value')

module.exports = function alwaysDone (val) {
  if (typeof val === 'function') {
    return letta.apply(this, arguments).then(lettaValue)
  }
  return lettaValue(val)
}

And few examples. For more see the documentation, examples and tests of always-done.

const fs = require('fs')
const alwaysDone = require('always-done')

Reading file as buffer with core module function fs.readFileSync.
This example also shows correct handling of optional arguments.

alwaysDone(fs.readFileSync, 'package.json')
.then(res => {
  console.log(Buffer.isBuffer(res)) // => true
}, console.error)

Parsing JSON string

alwaysDone('{"foo":"bar"}')
.then(JSON.parse)
.then(data => {
  console.log(data) // => { foo: 'bar' }
}, console.error)

Stringify given object and ident it

alwaysDone(JSON.stringify, {foo: 'bar'}, null, 2)
.then(data => {
  console.log(data)
  // =>
  // {
  //   "foo": "bar"
  // }
}, console.error)

Reading and parsing package.json

alwaysDone(fs.readFileSync, 'package.json', 'utf8')
.then(JSON.parse)
.then(data => {
  console.log(data.name) // => 'pkg-name'
}, console.error)

Related

• letta: Let's move to promises! Drop-in replacement for co@4, but on steroids. Accepts sync, async and generator functions.
• native-or-another: Always will expose native Promise if available, otherwise Bluebird but only if you don't give another promise module like q or promise or what you want.
• native-promise: Get native Promise or falsey value if not available.
• redolent: Simple promisify a callback-style function with sane defaults. Support promisify-ing sync functions.

Contributing

Pull requests and stars are always welcome. For bugs and feature requests, please create an issue.
But before doing anything, please read the CONTRIBUTING.md guidelines.

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