CODEWITHSUNDEEP
javascriptarraysobject
kr3w4
kr3w4

Reputation: 85

How to go through object that have array and sum the values?

I have a list of object that has date and values. I would like to create a new object that sums the total of values in the object. I have a solution so far but not satisfied my code and wondering if you have any better solution?

Also, I would like to display the most recent year in order. 

const dividendsYears = {
    1976: [
        0: {date: "1976-05-10", value: "0.00062"}
        1: {date: "1976-07-16", value: "0.00062"}
        2: {date: "1976-10-21", value: "0.00062"}
    ],
    1977: [
        0: {date: "1977-02-14", value: "0.00062"}
        1: {date: "1977-05-12", value: "0.00123"}
        2: {date: "1977-07-19", value: "0.00123"}
        3: {date: "1977-10-18", value: "0.00123"}
    ],
    1978: [
        0: {date: "1978-02-14", value: "0.00123"}
        1: {date: "1978-05-16", value: "0.00222"}
        2: {date: "1978-07-19", value: "0.00222"}
        3: {date: "1978-10-26", value: "0.00222"}
    ]
}

// Create new object that sum the total of value
let totalDividendsPerYear = {}
Object.entries(dividendsYears).forEach((entry, index) => {
    let sum = 0

    // Adds up dividends value per year
    entry[1].forEach((item) => (
        sum += Number(item.value)
    ))

    totalDividendsPerYear[entry[0]] = sum
});

// Reverse array to sort the recent date to the oldest date
const sortRecentDate = Object.assign([], totalDividendsPerYear).reverse();

Expected result:

{
    1978: 0.00789,
    1977: 0.0043100000000000005,
    1976: 0.00186
}

Upvotes: 0

Views: 75

Answers (3)

Mister Jojo
Mister Jojo

Reputation: 22320

I think I get the shorter one : ;)

const dividendsYears = {
1976: [ { date: "1976-05-10", value: "0.00062" }
      , { date: "1976-07-16", value: "0.00062" }
      , { date: "1976-10-21", value: "0.00062" }
      ],
1977: [ { date: "1977-02-14", value: "0.00062" }
      , { date: "1977-05-12", value: "0.00123" }
      , { date: "1977-07-19", value: "0.00123" }
      , { date: "1977-10-18", value: "0.00123" }
      ],
1978: [ { date: "1978-02-14", value: "0.00123" }
      , { date: "1978-05-16", value: "0.00222" }
      , { date: "1978-07-19", value: "0.00222" }
      , { date: "1978-10-26", value: "0.00222" }
      ]
};

const result = Object.entries(dividendsYears).reduce((r,x)=>{r[x[0]]=x[1].reduce((a,c)=>a+parseFloat(c.value),0); return r},{});

console.log( result )

Upvotes: 1

Akrion
Akrion

Reputation: 18515

You can do this with a single Object.keys and Array.reduce:

const data = { 1976: [ {date: "1976-05-10", value: "0.00062"}, {date: "1976-07-16", value: "0.00062"}, {date: "1976-10-21", value: "0.00062"} ], 1977: [ {date: "1977-02-14", value: "0.00062"}, {date: "1977-05-12", value: "0.00123"}, {date: "1977-07-19", value: "0.00123"}, {date: "1977-10-18", value: "0.00123"} ], 1978: [ {date: "1978-02-14", value: "0.00123"}, {date: "1978-05-16", value: "0.00222"}, {date: "1978-07-19", value: "0.00222"}, {date: "1978-10-26", value: "0.00222"} ] }

let result = Object.keys(data).reduce((r,k) => {
  r[k] = data[k].reduce((acc,c) => (+acc.value || acc || 0) + (+c.value))
  return r
}, {})

console.log(result)

You can also one line it with some sacrifice to the readability:

const data = { 1976: [ {date: "1976-05-10", value: "0.00062"}, {date: "1976-07-16", value: "0.00062"}, {date: "1976-10-21", value: "0.00062"} ], 1977: [ {date: "1977-02-14", value: "0.00062"}, {date: "1977-05-12", value: "0.00123"}, {date: "1977-07-19", value: "0.00123"}, {date: "1977-10-18", value: "0.00123"} ], 1978: [ {date: "1978-02-14", value: "0.00123"}, {date: "1978-05-16", value: "0.00222"}, {date: "1978-07-19", value: "0.00222"}, {date: "1978-10-26", value: "0.00222"} ] }

let result = Object.keys(data).reduce((r,k) => 
   (r[k] = data[k].reduce((a,c) => (+a.value || a || 0) + (+c.value))) && r, {})

console.log(result)

Upvotes: 2

Amir Popovich
Amir Popovich

Reputation: 29836

Here's a one liner solution:

const dividendsYears = {
    "1976": [
         {date: "1976-05-10", value: "0.00062"},
         {date: "1976-07-16", value: "0.00062"},
         {date: "1976-10-21", value: "0.00062"}
    ],
    "1977": [
         {date: "1977-02-14", value: "0.00062"},
         {date: "1977-05-12", value: "0.00123"},
         {date: "1977-07-19", value: "0.00123"},
        {date: "1977-10-18", value: "0.00123"}
    ],
    "1978": [
         {date: "1978-02-14", value: "0.00123"},
         {date: "1978-05-16", value: "0.00222"},
         {date: "1978-07-19", value: "0.00222"},
        {date: "1978-10-26", value: "0.00222"}
    ]
}

const result = Object.entries(dividendsYears).reduce((a,b) => { a[b[0]] = b[1].map(i => parseFloat(i.value)).reduce((k,j) => k + j); return a; },{});

document.write(JSON.stringify(result));

Upvotes: 1

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