How to sum the values in this object of objects in javascript?

Question

const ob = {
    a: 1,
    b: {
        c: 3,
        d: 6,
        e: {
            f: {
                g: 3,
                h: {
                    i: 5,
                    j: {
                        k: 7
                    }
                }
            }
        }
    }
};

Any methods to solve this code?

I have no idea how to solve this code.

For abovementioned input I would expect a result of 1 + 3 + 6 + 3 + 5 + 7 = 25. So what I want to return from a function sumObject(ob) is: 25

The real problem is how to get all the nested keys into one array. From there you can just do array.prototype.reduce(). — KoderM
– KoderM, Commented May 10, 2022 at 16:06

Nick Vu · Accepted Answer · 2022-05-10 16:12:11Z

5

You can try reduce with recursion

The condition for the sum is

If the current value is a number, sum it with result
If the current value is not a number (in your case, it's an object), call the function sumObject recursively with current result

const ob = {
  a: 1,
  b: {
    c: 3,
    d: 6,
    e: {
      f: {
        g: 3,
        h: {
          i: 5,
          j: {
            k: 7
          }
        }
      }
    }
  }
};

function sumObject(data, result = 0) {
  return Object.values(data).reduce((sum, value) => typeof value === 'number' ? sum + value : sumObject(value, sum), result)
}

console.log(sumObject(ob))

answered May 10, 2022 at 16:12

Nick Vu

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Comments

KoderM · Accepted Answer · 2022-05-10 16:23:34Z

1

If you don't understand some of the other answers, this is an easier solution to understand:

function sumObject(obj){
  
  let result = 0;
  
  for(let i of Object.values(obj)){ //we iterate through all values in obj
    
    if(typeof i == "number"){ //if the current value of i is a number
      
      result+=i; //then add that to the result
      
    } else { //otherwise, it will be an object
      
      result+=sumObject(i); //so we call the function on itself to iterate over this new object
      
    }
    
  }
  
  return result; //finally, we return the total
  
}

console.log(sumObject(ob));

edited May 10, 2022 at 16:23

answered May 10, 2022 at 16:15

KoderM

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Comments

madprops · Accepted Answer · 2022-05-10 16:11:01Z

0

You can do this to extract all values into an array of numbers and then sum that array:

const getObjectValues = (obj) => (obj && typeof obj === 'object')
 ? Object.values(obj).map(getObjectValues).flat()
 : [obj]


let nums = getObjectValues(ob)

let sum = nums.reduce((a, b) => a + b, 0)

answered May 10, 2022 at 16:11

madprops

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Comments

Hassan Imam · Accepted Answer · 2022-05-10 16:13:00Z

0

You can recursively sum the value of each object using array#reduce and Object.values()

const ob = { a: 1, b: { c: 3, d: 6, e: { f: { g: 3, h: { i: 5, j: { k: 7 } } } } } },
      getSum = o =>
        Object.values(o).reduce((s, v) => {
          s += typeof v === 'object' ? getSum(v): v;
          return s;
         }, 0);
console.log(getSum(ob));

answered May 10, 2022 at 16:13

Hassan Imam

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Comments

mstephen19 · Accepted Answer · 2022-05-10 16:39:02Z

Try recursion. This will support any amount of nested object at any level of nesting.

const sumAllNumbers = (object, total = 0) => {
    const nextValues = [];

    for (const value of Object.values(object)) {
        if (typeof value === 'number') total += value;
        if (typeof value === 'object') nextValues.push(Object.values(value));
    }

    if (!nextValues.length) return total;

    return sumAllNumbers(nextValues.flat(), total);
};

// adds up to 25
const testCase1 = {
    a: 1,
    b: {
        c: 3,
        d: 6,
        e: {
            f: {
                g: 3,
                h: {
                    i: 5,
                    j: {
                        k: 7,
                    },
                },
            },
        },
    },
};

// adds up to 30
const testCase2 = {
    a: 1,
    b: 2,
    c: {
        a: 1,
        b: 2,
        c: 3,
        d: {
            a: 5,
            b: {
                c: {
                    d: {
                        e: 1,
                    },
                },
            },
        },
    },
    d: {
        g: {
            f: {
                c: 10,
            },
        },
    },
    e: {
        f: {
            a: 1,
            g: {
                a: 4,
            },
        },
    },
};

// Your original test case
console.log(sumAllNumbers(testCase1));

// My much more demanding test case
console.log(sumAllNumbers(testCase2));

Nina Scholz · Accepted Answer · 2022-05-10 16:50:46Z

You could get the value of the objects and check if the value is an object, then take the result of the nested objects or call the handed over sum function for accumulator and actual value.

This approach works with a function which takes

an object
an accumulator function
a start value

This function works as well for getting all values with different accumulator function and an array as startValue.

const
    reduce = (object, fn, startValue) => Object
        .values(object)
        .reduce(
            (r, v) => v && typeof v === 'object' ? reduce(v, fn, r) : fn(r, v),
            startValue
        ),
    data = { a: 1, b: { c: 3, d: 6, e: { f: { g: 3, h: { i: 5, j: { k: 7 } } } } } },
    total = reduce(data, (a, b) => a + b, 0);

console.log(total);

MoRe · Accepted Answer · 2022-05-10 16:55:15Z

0

const ob = {
    a: 1,
    b: {
        c: 3,
        d: 6,
        e: {
            f: {
                g: 3,
                h: {
                    i: 5,
                    j: {
                        k: 7
                    }
                }
            }
        }
    }
}; 

const sum = data =>
   Object
   .keys(data)
   .reduce((a,b) => a + (typeof(s = data[b]) == "number" ? s : sum(s)), 0);

console.log(sum(ob))

edited May 10, 2022 at 16:55

answered May 10, 2022 at 16:27

MoRe

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