Calculate the number of days required for the value in an item to multiply by two

Question

Calculate the number of days required for the value in an item to multiply by two

I'm currently working on a JavaScript project to create a table displaying the latest number of coronavirus cases. I've reached a point where I want to add a column showing how many days it took for the confirmedCases numbers to double. Here's an example:

{
  "message": "Success",
  "source": "JHU CSSE",
  "sourceURL": "https://github.com/CSSEGISandData/2019-nCoV",
  "updateDate": "2020-03-22T11:08:41.651Z",
  "data": {
    "3/15/20": {
      "Afghanistan": 16,
      "Albania": 42,
      
      ......
      // Truncated data for brevity

      "US": 3499,
      "Uganda": 0,
      "Ukraine": 3,
      "United Arab Emirates": 98,
      "United Kingdom": 1145,
      "Uruguay": 4,
      "Uzbekistan": 1,
      "Venezuela": 10,
      "Vietnam": 56,
      "Zambia": 0,
      "Zimbabwe": 0
    },
    
    ......
    // More data entries for each day
    
  }
}

Wouldn't it be interesting if we could obtain an object that shows the number of days it took for the cases in each country to double? That might provide valuable insights into the spread of the virus worldwide.

javascript arrays json object

Answer 1

Answer №1

Track the initial count of infected individuals by country and then loop through the countries to determine if the count doubles the initial number.

// Keep track of days
let days = 0;

const countriesWithDoubleDayCount = {};
const dates = Object.keys(data.data);
const countries = Object.values(data.data);

// Initialize countries object with count set to zero
const groupByCountries = Object.keys(data.data["3/15/20"]).reduce((accu, name) => {
    accu[name] = 0;
    return accu;
}, {});

const initialCountCountryWise = {};

const doubleCount = countries.reduce((a, country, i) => {
    if (i < dates.length - 1) {
        // Calculate date difference
        days += Math.abs((new Date(dates[i + 1]) - new Date(dates[i])) / (1000 * 60 * 60 * 24), 10);
    }

    const countries = Object.entries(country);

    countries.forEach(([name, count]) => {
        // First Record 
        if (i == 0) {
            // Track initial count of infected people by country.
            initialCountCountryWise[name] = count !== 0 ? count : 1;
        }

        a[name] = count;
        const double = initialCountCountryWise[name] * 2;

        // Check if current count is greater than double the initial count
        // If it is, add to countriesWithDoubleDayCount Object.
        if (a[name] >= double && !countriesWithDoubleDayCount.hasOwnProperty(name)) {
            countriesWithDoubleDayCount[name] = days;
        }
    });

    return a;
}, groupByCountries);

console.log(countriesWithDoubleDayCount);

Note - Unfortunately unable to include a live Javascript code snippet due to character limitations.

Answer 2

Track the initial count of infected individuals by country and then loop through the countries to determine if the count doubles the initial number.

// Keep track of days
let days = 0;

const countriesWithDoubleDayCount = {};
const dates = Object.keys(data.data);
const countries = Object.values(data.data);

// Initialize countries object with count set to zero
const groupByCountries = Object.keys(data.data["3/15/20"]).reduce((accu, name) => {
    accu[name] = 0;
    return accu;
}, {});

const initialCountCountryWise = {};

const doubleCount = countries.reduce((a, country, i) => {
    if (i < dates.length - 1) {
        // Calculate date difference
        days += Math.abs((new Date(dates[i + 1]) - new Date(dates[i])) / (1000 * 60 * 60 * 24), 10);
    }

    const countries = Object.entries(country);

    countries.forEach(([name, count]) => {
        // First Record 
        if (i == 0) {
            // Track initial count of infected people by country.
            initialCountCountryWise[name] = count !== 0 ? count : 1;
        }

        a[name] = count;
        const double = initialCountCountryWise[name] * 2;

        // Check if current count is greater than double the initial count
        // If it is, add to countriesWithDoubleDayCount Object.
        if (a[name] >= double && !countriesWithDoubleDayCount.hasOwnProperty(name)) {
            countriesWithDoubleDayCount[name] = days;
        }
    });

    return a;
}, groupByCountries);

console.log(countriesWithDoubleDayCount);

Note - Unfortunately unable to include a live Javascript code snippet due to character limitations.

Calculate the number of days required for the value in an item to multiply by two

Answer №1

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