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unboundedpress/node_modules/slide/lib/async-map-ordered.js

66 lines
1.7 KiB
JavaScript

6 years ago
throw new Error("TODO: Not yet implemented.")
/*
usage:
Like asyncMap, but only can take a single cb, and guarantees
the order of the results.
*/
module.exports = asyncMapOrdered
function asyncMapOrdered (list, fn, cb_) {
if (typeof cb_ !== "function") throw new Error(
"No callback provided to asyncMapOrdered")
if (typeof fn !== "function") throw new Error(
"No map function provided to asyncMapOrdered")
if (list === undefined || list === null) return cb_(null, [])
if (!Array.isArray(list)) list = [list]
if (!list.length) return cb_(null, [])
var errState = null
, l = list.length
, a = l
, res = []
, resCount = 0
, maxArgLen = 0
function cb (index) { return function () {
if (errState) return
var er = arguments[0]
var argLen = arguments.length
maxArgLen = Math.max(maxArgLen, argLen)
res[index] = argLen === 1 ? [er] : Array.apply(null, arguments)
// see if any new things have been added.
if (list.length > l) {
var newList = list.slice(l)
a += (list.length - l)
var oldLen = l
l = list.length
process.nextTick(function () {
newList.forEach(function (ar, i) { fn(ar, cb(i + oldLen)) })
})
}
if (er || --a === 0) {
errState = er
cb_.apply(null, [errState].concat(flip(res, resCount, maxArgLen)))
}
}}
// expect the supplied cb function to be called
// "n" times for each thing in the array.
list.forEach(function (ar) {
steps.forEach(function (fn, i) { fn(ar, cb(i)) })
})
}
function flip (res, resCount, argLen) {
var flat = []
// res = [[er, x, y], [er, x1, y1], [er, x2, y2, z2]]
// return [[x, x1, x2], [y, y1, y2], [undefined, undefined, z2]]