Calculating 2 object keys/columns from array of objects Javascript [duplicate]

问题

So I was working on the some column merging and filtering,but I am having trouble calculating 2 object keys (columns) from an array of objects and then mapping that result to an object key to a new array

Example:

var foodRevenue = [{
    "Month": "2011-01",
    "week1_Revenue": "100.00",
    "week2_Revenue": "300.51",
    "Week3_Reenue": "200.09",
    "Month1_TotalRevenue": "0"
}];

I want to calculate the sum of week1, week2, and week3 and the result to map on Month1_TotalRevenue. Then creating a new array that would filter Month and Month1_TotalRevenue to that array. Like so:

{"Month": "2011-01", "Month1_TotalRevenue": "600.60"}

Any suggestions would be appreciated

回答1:

You may destructure your object properties and sum up desired ones, using Array.prototype.reduce():

const  foodRevenue = {
      "Month": "2011-01",
      "week1_Revenue": "100.00",
      "week2_Revenue": "300.51",
      "Week3_Reenue": "200.09",
      "Month1_TotalRevenue": "0"
    },
    {Month, Month1_TotalRevenue, week1_Revenue,...revenue} = foodRevenue,
    result = {
      Month,
      week1_Revenue,
      Month1_TotalRevenue: 
        Object
          .values({...revenue,week1_Revenue})
          .reduce((s,r) => s+=+r, +Month1_TotalRevenue)
          .toFixed(2)
    }
    
console.log(result)

回答2:

You can use the function Map along with the function reduce as follow

This approach uses an array with the keys in the desired output, that way it's more dynamic.

let foodRevenue = [{"Month": "2011-01",    "week1_Revenue": "100.00",    "week2_Revenue": "300.51",    "Week3_Reenue": "200.09",    "Month1_TotalRevenue": "0"}];
let inArray = ["Month", "week1_Revenue"];
let accumulator = "Month1_TotalRevenue";
let result = foodRevenue.map(revenue => {
  let obj = Object.entries(revenue).reduce((r, [k, v]) => {
    if (inArray.includes(k)) r = Object.assign(r, {[k]: revenue[k]});
    return Object.assign(r, {[accumulator]: +(r[accumulator] || (r[accumulator] = 0)) + +v})
  }, {});
  
  obj[accumulator] = obj[accumulator].toFixed(2);
  return obj;
});

console.log(result);

回答3:

@Yevgen-Gorbunkov's answer is more concise...

    var foodRevenue = [{
        "Month": "2011-01",
        "week1_Revenue": "100.00",
        "week2_Revenue": "300.51",
        "Week3_Revenue": "200.09",
        "Month1_TotalRevenue": "0"
    }];


 let yearlyRevenue = foodRevenue.map((foodRevenue) => {
    let costs = 0

    for(let [key, value] of Object.entries(foodRevenue)) {
      if(key.indexOf('_Revenue') > -1){ // check if the key has _Revenue suffix
        costs += +value // +value change string to number
      }
    }

    console.log(costs);
    
    const transformed = { 
        Month: foodRevenue.Month,
        Month1_TotalRevenue: costs
    }

    return transformed
});

console.log(yearlyRevenue)

来源：https://stackoverflow.com/questions/60639632/calculating-2-object-keys-columns-from-array-of-objects-javascript

标签

javascript

arrays

object

sum