JAVASCRIPT

sum of array of objects javascript

var accounts = [
  { name: 'James Brown', msgCount: 123 },
  { name: 'Stevie Wonder', msgCount: 22 },
  { name: 'Sly Stone', msgCount: 16 },
  { name: 'Otis Redding', msgCount: 300 }  // Otis has the most messages
];

// get sum of msgCount prop across all objects in array
var msgTotal = accounts.reduce(function(prev, cur) {
  return prev + cur.msgCount;
}, 0);

console.log('Total Messages:', msgTotal); // Total Messages: 461

javascript sum array of objects

arr = [{x:1}, {x:3}]

arr.reduce((accumulator, current) => accumulator + current.x, 0);

js get sum of array of objects

const getSumByKey = (arr, key) => {
  return arr.reduce((accumulator, current) => accumulator + Number(current[key]), 0)
}

arr = [{x:1}, {x:3}]
getSumByKey(arr, 'x') // returns 4

javascript sum of number in object array

  run.addEventListener("click", function () {
    let sum = people.reduce(function (a, b) { // function(previousValue, currentValue)
      return {
        age: a.age + b.age, //select age in object array
      };
    });
    console.log(sum); //output sum of ages
  });

javascript object array sum of values in object

const fruitTally = fruit.reduce((currentTally, currentFruit) => {
  currentTally[currentFruit] = (currentTally[currentFruit] || 0) + 1 
  return currentTally
} , {})
// returns {"apple":3,"banana":3,"cherry":2,"mango":2,"apricot":1,"guava":2}

sum an array of objects

let cart = [
  {
    name: "JavaScript book",
    price: 4,
  },
  {
    name: "UGG Women's Hazel Ankle Boot",
    price: 79,
  },
  {
    name: "OXO Good Grips 11-Inch Balloon Whisk",
    price: 9,
  },
];

// totalPrice is 92

let totalPrice = cart.reduce(function (accumulator, item) {
  return accumulator + item.price;
}, 0);