What is the best way to utilize a reduce function to eliminate the need for looping through an object in JavaScript?

Question

What is the best way to utilize a reduce function to eliminate the need for looping through an object in JavaScript?

Currently, my code looks like this:

  const weekdays = eachDay.map((day) => format(day, 'EEE'));

  let ret = { Su: '', Mo: '', Tu: '', We: '', Th: '', Fr: '', Sa: '' };
  weekdays.forEach((day, index) => {
    ret[Object.keys(ret)[index] as DaysOfWeekMui] = day;
  });

I was told by a fellow team member that I could improve this code by using a reduce method instead of manually defining the object ret. However, I'm not exactly sure how to do that. Any guidance on this issue would be greatly appreciated.

Thank you for your assistance.

javascript arrays typescript reduce

Answer 1

Answer №1

When I utilize the reduce method, it is usually to convert a collection of items into a singular item.

From your provided example, you are cycling through an array of weekdays and transforming it into an object.

To refactor your current code using reduce, you would implement it in this manner:

const result = weekdays.reduce((accumulator, day) => {
   return { ...accumulator, [day.slice(0, 2)]: day }
}, /* initial value: */ {})

This script will loop through the weekdays array and execute the reduce function. The function takes in accumulator, which contains the outcome from the previous iteration (or the starting value in the first iteration), as well as the item from the array on which you're applying reduce.

If we have an array like:

["Monday", "Tuesday"]

, the resulting object from the reduce function will be:

{
  Mo: "Monday",
  Tu: "Tuesday"
}

Answer 2

When I utilize the reduce method, it is usually to convert a collection of items into a singular item.

From your provided example, you are cycling through an array of weekdays and transforming it into an object.

To refactor your current code using reduce, you would implement it in this manner:

const result = weekdays.reduce((accumulator, day) => {
   return { ...accumulator, [day.slice(0, 2)]: day }
}, /* initial value: */ {})

This script will loop through the weekdays array and execute the reduce function. The function takes in accumulator, which contains the outcome from the previous iteration (or the starting value in the first iteration), as well as the item from the array on which you're applying reduce.

If we have an array like:

["Monday", "Tuesday"]

, the resulting object from the reduce function will be:

{
  Mo: "Monday",
  Tu: "Tuesday"
}

Answer 3

Answer №2

Array#reduce is a handy method that requires a callback function and an initial value as arguments. In this scenario, the variable ret serves as the initial value. To simplify your code, you can refactor it like this:

const ret = weekdays.reduce((obj, day, index) => {
  obj[obj.keys(obj)[index] as DaysOfWeekMui] = day
  return obj
}, { Su: '', Mo: '', Tu: '', We: '', Th: '', Fr: '', Sa: '' })

Answer 4

Array#reduce is a handy method that requires a callback function and an initial value as arguments. In this scenario, the variable ret serves as the initial value. To simplify your code, you can refactor it like this:

const ret = weekdays.reduce((obj, day, index) => {
  obj[obj.keys(obj)[index] as DaysOfWeekMui] = day
  return obj
}, { Su: '', Mo: '', Tu: '', We: '', Th: '', Fr: '', Sa: '' })

What is the best way to utilize a reduce function to eliminate the need for looping through an object in JavaScript?

Answer №1

Answer №2

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