My question is how to get total number of id's created per month. The below is my code fetching response from Mysql Db.
const dashboardOverview = async (req,res,next) => {
var ordersPerMonth = await Orders.findAll({attributes:['od_id','od_created_date']});
for(var i = 0; i < ordersPerMonth.length ; i++){
let dataItem = {};
for(const [key,value] of Object.entries(ordersPerMonth[i].dataValues)){
dataItem[key.replace("od_","")] = value;
}
dataStore.push(dataItem);
}
console.log(dataStore)
const arr = dataStore;
console.log(arr)
const counts = arr.reduce((m, { created_date }) => {
// Create a key from the year and month, eg "2021-08"
const key = created_date.substr(0, 7)
// Increment the count for the key
return m.set(key, (m.get(key) ?? 0) + 1)
}, new Map())
console.log(Object.fromEntries(counts))
}
Now in response I wanted monthname and total count of orders placed that month. For ex- [ January-21 : 23, February-21: 45......December-21: 56] But while using reduce() function I am getting type error:arr.reduce is not a function. I hope my query is clear.
This kind of result can be achieved by reducing your array to a map of month counts.
const formatter = new Intl.DateTimeFormat("en", {
year: "2-digit",
month: "long",
})
const formatKey = date => formatter.format(date).replace(" ", "-")
const dashboardOverview = async (req, res, next) => {
const orders = await Orders.findAll({
attributes: ["od_id", "od_created_date"]
})
const ordersPerMonth = orders.reduce((map, { od_created_date }) => {
// assuming od_created_date is already a `Date` instance
const key = formatKey(od_created_date).replace(" ", "-")
return map.set(key, (map.get(key) ?? 0) + 1)
}, new Map())
const asObject = Object.fromEntries(ordersPerMonth)
console.log(asObject)
// and if you want to respond with JSON
res.json(asObject)
}