JavaScript -Summen -Array von Objekten
arr = [{x:1}, {x:3}]
arr.reduce((accumulator, current) => accumulator + current.x, 0);
Bhishma'S
arr = [{x:1}, {x:3}]
arr.reduce((accumulator, current) => accumulator + current.x, 0);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: 461const getSumByKey = (arr, key) => {
return arr.reduce((accumulator, current) => accumulator + Number(current[key]), 0)
}
arr = [{x:1}, {x:3}]
getSumByKey(arr, 'x') // returns 4
class fruitCollection extends Array {
sum(key) {
return this.reduce((a, b) => a + (b[key] || 0), 0);
}
}
const fruit = new fruitCollection(...[
{ description: 'orange', Amount: 50},
{ description: 'orange', Amount: 50},
{ description: 'apple', Amount: 75},
{ description: 'kiwi', Amount: 35},
{ description: 'watermelon', Amount: 25 },]);
console.log(fruit.sum('Amount')); 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
});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}