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Contents
"use strict";
var reduce = require("reducible/reduce")
var reducible = require("reducible/reducible")
var end = require("reducible/end")
var isError = require("reducible/is-error")
function merge(source) {
/**
Merges given collection of collections to a collection with items of
all nested collections. Note that items in the resulting collection
are ordered by the time rather then index, in other words if item from
the second nested collection is deliver earlier then the item
from first nested collection it will in appear earlier in the resulting
collection.
print(merge([ [1, 2], [3, 4] ])) // => < 1 2 3 4 >
**/
return reducible(function accumulateMerged(next, initial) {
var state = initial
var open = 1
function forward(value) {
if (value === end) {
open = open - 1
if (open === 0) return next(end)
} else {
state = next(value, state)
}
return state
}
reduce(source, function accumulateMergeSource(nested) {
// If there is an error or end of `source` collection just pass it
// to `forward` it will take care of detecting weather it's error
// or `end`. In later case it will also figure out if it's `end` of
// result to and act appropriately.
if (nested === end) return forward(end)
if (isError(nested)) return forward(nested)
// If `nested` item is not end nor error just `accumulate` it via
// `forward` that keeps track of all collections that are bing forwarded
// to it.
open = open + 1
reduce(nested, forward, null)
}, initial)
})
}
module.exports = merge
Version data entries
5 entries across 2 versions & 1 rubygems