Summing values in es6 (TypeScript) without explicitly knowing their corresponding keys

Question

Summing values in es6 (TypeScript) without explicitly knowing their corresponding keys

I am facing a challenge with an object that has changeable keys, which I do not want to rely on. The keys in this object are not fixed. Here is an example:

interface Inf {
 [key: string]: number
}


const obj: Inf = {
  '2020-01-01': 4,
  '2020-01-02': 5,
}

const obj2: Inf = {
  '2020-01-05': 10,
  '2020-02-10': 15,
}

const finalObj = { one: obj, two: obj2, ... }

My goal is to calculate the sum of 10 + 15 + 4 + 5 regardless of their key names. I have lodash installed, which offers a method called sumBy. However, it requires input as an array, while mine is a full object.

Is there a way to achieve a total of 34 from this object efficiently? What would be the best approach for handling such an operation?

let x = 0

Object.values(obj).forEach(o => {
   x += o
})

While the above solution works, I'm curious if there is a better or more concise way to accomplish this task. Any suggestions for a shorter and faster implementation?

javascript typescript ecmascript-6

Answer 1

Answer №1

One way to handle nested objects is by using a recursive approach.

const
    calculateTotal = object => Object
        .values(object)
        .reduce((sum, value) => sum + (value && typeof value === 'object' ? calculateTotal(value) : value), 0),
    obj1 = { '2020-01-01': 4, '2020-01-02': 5 },
    obj2 = { '2020-01-05': 10, '2020-02-10': 15 },
    finalObj = { obj1, obj2 },
    totalSum = calculateTotal(finalObj);

console.log(totalSum);

Answer 2

One way to handle nested objects is by using a recursive approach.

const
    calculateTotal = object => Object
        .values(object)
        .reduce((sum, value) => sum + (value && typeof value === 'object' ? calculateTotal(value) : value), 0),
    obj1 = { '2020-01-01': 4, '2020-01-02': 5 },
    obj2 = { '2020-01-05': 10, '2020-02-10': 15 },
    finalObj = { obj1, obj2 },
    totalSum = calculateTotal(finalObj);

console.log(totalSum);

Answer 3

Answer №2

If you're looking to calculate the sum of values in objects with only one level like in your provided example, you can employ Object.values along with reduce.

const obj = {
    "2020-01-01": 4,
    "2020-01-02": 5,
};
const obj2 = {
    "2020-01-05": 10,
    "2020-02-10": 15,
};
const finalObj = { one: obj, two: obj2 };

const result = Object.values(finalObj).reduce((a, b) => a + Object.values(b).reduce((a1, b1) => a1 + b1, 0), 0);

console.log(result);

Answer 4

If you're looking to calculate the sum of values in objects with only one level like in your provided example, you can employ Object.values along with reduce.

const obj = {
    "2020-01-01": 4,
    "2020-01-02": 5,
};
const obj2 = {
    "2020-01-05": 10,
    "2020-02-10": 15,
};
const finalObj = { one: obj, two: obj2 };

const result = Object.values(finalObj).reduce((a, b) => a + Object.values(b).reduce((a1, b1) => a1 + b1, 0), 0);

console.log(result);

Answer 5

Answer №3

In the comments, you specified that you are only working with a single layer (as indicated in the question). My approach would involve using a straightforward nested loop:

let sum = 0;
for (const obj of Object.values(finalObj)) {  // Iterate through the objects
    for (const value of Object.values(obj)) { // Iterate through the values
        sum += value;
    }
}

This method closely resembles Nikita's solution, but with explicit loops. :-)

See a live example below:

const obj = {
    "2020-01-01": 4,
    "2020-01-02": 5,
};
const obj2 = {
    "2020-01-05": 10,
    "2020-02-10": 15,
};
const finalObj = { one: obj, two: obj2 };

let sum = 0;
for (const obj of Object.values(finalObj)) {
    for (const value of Object.values(obj)) {
        sum += value;
    }
}

console.log(sum);

Answer 6

In the comments, you specified that you are only working with a single layer (as indicated in the question). My approach would involve using a straightforward nested loop:

let sum = 0;
for (const obj of Object.values(finalObj)) {  // Iterate through the objects
    for (const value of Object.values(obj)) { // Iterate through the values
        sum += value;
    }
}

This method closely resembles Nikita's solution, but with explicit loops. :-)

See a live example below:

const obj = {
    "2020-01-01": 4,
    "2020-01-02": 5,
};
const obj2 = {
    "2020-01-05": 10,
    "2020-02-10": 15,
};
const finalObj = { one: obj, two: obj2 };

let sum = 0;
for (const obj of Object.values(finalObj)) {
    for (const value of Object.values(obj)) {
        sum += value;
    }
}

console.log(sum);

Summing values in es6 (TypeScript) without explicitly knowing their corresponding keys

Answer №1

Answer №2

Answer №3

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