prod/index.js

Asynchronous npm dependency walker

'use strict'

var readInstalled = require('read-installed')
var asyncMixin = require('async-mixin')
var advisable = require('advisable')

var Processor = module.exports = function Processor (start) {
  if (!(this instanceof Processor)) return new Processor(start)
  this.start = start || process.cwd()
  this.dependencies = []
  this.initialized = false
}

// inherit async methods
Processor.prototype = asyncMixin('dependencies')
var asyncMethods = Object.keys(Processor.prototype)
Processor.prototype.load = function (fn) {
  var self = this
  var visited = {}
  readInstalled(this.start, function (err, dep) {
    if (err) return fn(err)
    getDependencies(dep, self.dependencies, visited)
    self.initialized = true
    return fn(null, self.dependencies)
  })
}

advisable.async.call(Processor.prototype)

asyncMethods.forEach(function (method) {
  // Ensure we have some dependencies to work with before
  // calling any async functions.
  Processor.prototype.before(method, function () {
    var callback = arguments[arguments.length - 1]
    if (this.initialized) return callback()

    this.load(callback)
  })
})

function getDependencies (mod, result, visited) {
  visited = visited || {}
  if (visited[mod.realPath]) return result
  visited[mod.realPath] = true

  result = result || []
  result.push(mod)
  var dependencies = mod.dependencies || []
  Object.keys(dependencies).forEach(function (dep) {
    getDependencies(mod.dependencies[dep], result, visited)
  })
  return result
}