for each group by date in coffeescript - coffeescript

Question

which pulls data from and reformats it.
Promise = require "bluebird"
request = Promise.promisify require "request"
moment = require "moment"
cdn = require('config').server.cloudFrontDomain
toTitleCase = require "titlecase"
exports.getStocks = (path) ->
return new Promise (resolve, reject) ->
request path
.then (body) ->
germanStock = []
germanStocks = JSON.parse body.body
germanStocks.forEach (stock) ->
obj = {}
this.parsePart = (remaining) ->
value = remaining.value
dashIndex = value.lastIndexOf '-'
if dashIndex != -1
remaining.value = value.substring 0, dashIndex - 1
return value.substring(dashIndex + 1).trim()
else
return ''
remaining =
value: stock.name
size = parsePart remaining
colour = parsePart remaining
name = remaining.value
sku = stock.sku
styleId = sku.split(/-/)[0]
colorcode = /^(.*)-(.*)([0-9])$/.exec(sku)?[2]
bgStyle = "url(//#{cdn}/assets/product_shots/thumbs/#{styleId}-#{colorcode}.jpg)"
obj.id = sku
obj.name = name
obj.colorUrl = bgStyle
obj.colour = toTitleCase(colour.toLowerCase())
obj.size = size
obj.stock = stock.stock
obj.inProduction = ''
obj.office = 'DE'
stock.preorders.forEach (i, idx) ->
date = moment(i.date).format('DD-MM-YYYY')
if idx != stock.preorders.length - 1
obj.inProduction = obj.inProduction.concat i.amount + ' due on ' + date + ', '
else
obj.inProduction = obj.inProduction.concat i.amount + ' due on ' + date
germanStock.push obj
resolve germanStock
.catch (err) ->
reject err
where my data is like:
{
"id":1,
"stamp":"2014-09-25T12:55:30Z",
"name":" MENS T-SHIRT - BRIGHT BLUE - XS",
"sku":"SS01-BB0",
"stock":81,
"active":true,
"preorders":[
{
"id":92549,
"amount":160,
"date":"2016-06-19T22:00:00Z"
},
{
"id":92549,
"amount":200,
"date":"2016-06-19T22:00:00Z"
},
{
"id":92549,
"amount":1000,
"date":"2016-06-21T22:00:00Z"
}
],
"discountMatrix":0.0,
"stockNormalized":81,
"preOrdersSum":1360
},
{
"id":2,
"stamp":"2014-09-25T12:55:30Z",
"name":" MENS T-SHIRT - BRIGHT BLUE - S",
"sku":"SS01-BB1",
"stock":339,
"active":true,
"preorders":[
{
"id":92551,
"amount":240,
"date":"2016-06-19T22:00:00Z"
},
{
"id":92438,
"amount":160,
"date":"22016-06-19T22:00:00Z"
}
],
"discountMatrix":0.0,
"stockNormalized":339,
"preOrdersSum":400
},
what is the correct way to group each preorders quantity that is on the same date, so that instead of getting:
160 due on 19-06-2016, 200 due on 19-06-2016, 1000 due on 21-06-2016
i get 360 due on 19-06-2016, 1000 due on 21-06-2016
any advice much appreciated.

Answer 1

You could just use an object with the date as key and the total amount for the date as value.
For each preorder, add it's amount at it's date index in this object. At the end of the iteration print the content of the object:
moment = require "moment"
data = [
{
id:1
stamp: "2014-09-25T12:55:30Z"
name: " MENS T-SHIRT - BRIGHT BLUE - XS"
sku: "SS01-BB0"
stock:81
active:true
preorders:[
{
id:92549
amount:160
date: "2016-06-19T22:00:00Z"
}
{
id:92549
amount:200
date: "2016-06-19T22:00:00Z"
}
{
id:92549
amount:1000
date: "2016-06-21T22:00:00Z"
}
]
discountMatrix:0.0
stockNormalized:81
preOrdersSum:1360
}
]
obj = {}
obj.inProduction = ""
amountByDate = {}
# for each document in your data
for doc in data
# for each preorder in your document
for preorder in doc.preorders
# add it's amount in the index equals to it's date
if amountByDate[preorder.date]
amountByDate[preorder.date] += preorder.amount
else
# or create the index with the value if it doesn't exist
amountByDate[preorder.date] = preorder.amount
for date, amount of amountByDate
if obj.inProduction != ""
obj.inProduction = obj.inProduction.concat ", #{amount} due on #{moment(date).format('DD-MM-YYYY')}"
else
obj.inProduction = obj.inProduction.concat "#{amount} due on #{moment(date).format('DD-MM-YYYY')}"
console.log obj.inProduction
Result:
360 due on 20-06-2016, 1000 due on 22-06-2016