Using Javascript's Array.reduce() function causes the page to crash with Error Code 6

Question

Using Javascript's Array.reduce() function causes the page to crash with Error Code 6

Everything runs smoothly on the webpage unless I provide an initial value, causing a TypeError due to only one remaining element (as expected). In an attempt to fix this, I decided to pass 0 as the initial value for the reduce function (line 4 in the code snippet below). Unfortunately, this action results in the entire page breaking with error code 6.

The goal I'm aiming for: My objective is to sum all elements within an array, append that sum to another array, eliminate the first element, and repeat the process until no elements remain. At that point, I want the reduce() function to return 0, hence my need to supply an initial value of 0.

function partsSums(ls) {
  let sumArr = [];
  while (ls.length >= 0) {
    sumArr.push(ls.reduce((acc, cur) => acc + cur, 0));
    ls.shift();
  }
  return sumArr;
}

partsSums([0, 1, 3, 6, 10]);

The desired output I am seeking: [20, 20, 19, 16, 10, 0]

https://i.sstatic.net/rbsSJ.png

javascript arrays reduce array.prototype.map

Answer 1

Answer №1

Here is a method you can use:

function calculateSums(inputList)
  {
  let sumArray = []
    , lengthOfList    = inputList.length
    ;
  while ( lengthOfList >= 0)
    {
    sumArray.push(inputList.reduce((accumulator, current) => accumulator + current, 0))
    inputList.shift()
    --lengthOfList
    }
  return sumArray
  }

console.log(JSON.stringify( calculateSums([0, 1, 3, 6, 10])  ))

.as-console-wrapper { max-height: 100% !important; top: 0; }

Answer 2

Here is a method you can use:

function calculateSums(inputList)
  {
  let sumArray = []
    , lengthOfList    = inputList.length
    ;
  while ( lengthOfList >= 0)
    {
    sumArray.push(inputList.reduce((accumulator, current) => accumulator + current, 0))
    inputList.shift()
    --lengthOfList
    }
  return sumArray
  }

console.log(JSON.stringify( calculateSums([0, 1, 3, 6, 10])  ))

.as-console-wrapper { max-height: 100% !important; top: 0; }

Answer 3

Answer №2

There is a critical issue in your code with the condition ls.length >= 0. This condition is causing an infinite loop to occur. To fix this, simply change it to ls.length > 0

Recommendation

It appears that you are aiming for a cumulative summation from right to left. However, the current implementation of your function is not very efficient. Consider using suffix-sum as a better approach to solve this problem.

const suffixSum = arr => {
  const res = [];
  const {length} = arr;
  res[length] = 0;

  for (let i = length - 1; i >= 0; i--) {
    res[i] = res[i+1] + arr[i];
  }
  
  return res;
}

console.log(suffixSum([0, 1, 3, 6, 10]));

The suggested algorithm has a time complexity of O(n), whereas your current algorithm has a time complexity of O(n^2).

Answer 4

There is a critical issue in your code with the condition ls.length >= 0. This condition is causing an infinite loop to occur. To fix this, simply change it to ls.length > 0

Recommendation

It appears that you are aiming for a cumulative summation from right to left. However, the current implementation of your function is not very efficient. Consider using suffix-sum as a better approach to solve this problem.

const suffixSum = arr => {
  const res = [];
  const {length} = arr;
  res[length] = 0;

  for (let i = length - 1; i >= 0; i--) {
    res[i] = res[i+1] + arr[i];
  }
  
  return res;
}

console.log(suffixSum([0, 1, 3, 6, 10]));

The suggested algorithm has a time complexity of O(n), whereas your current algorithm has a time complexity of O(n^2).

Answer 5

Answer №3

It has been highlighted in the responses that you are encountering an infinite loop due to the fact that the array's length will never drop below 0.

As illustrated in alternative solutions, you can resolve this by adjusting the condition to ls.length > 0. However, by doing so, you will miss the scenario where you need to insert 0 into the result during the last iteration when the array is empty.

Rather than checking the length within the while() condition, evaluate it after executing reduce() and then break out of the loop accordingly.

function splitIntoParts(ls) {
  let totalArr = [];
  while (true) {
    totalArr.push(ls.reduce((acc, cur) => acc + cur, 0));
    if (ls.length == 0) {
      break;
    }
    ls.shift();
  }
  return totalArr;
}

console.log(splitIntoParts([0, 1, 3, 6, 10]));

Answer 6

It has been highlighted in the responses that you are encountering an infinite loop due to the fact that the array's length will never drop below 0.

As illustrated in alternative solutions, you can resolve this by adjusting the condition to ls.length > 0. However, by doing so, you will miss the scenario where you need to insert 0 into the result during the last iteration when the array is empty.

Rather than checking the length within the while() condition, evaluate it after executing reduce() and then break out of the loop accordingly.

function splitIntoParts(ls) {
  let totalArr = [];
  while (true) {
    totalArr.push(ls.reduce((acc, cur) => acc + cur, 0));
    if (ls.length == 0) {
      break;
    }
    ls.shift();
  }
  return totalArr;
}

console.log(splitIntoParts([0, 1, 3, 6, 10]));

Using Javascript's Array.reduce() function causes the page to crash with Error Code 6

Answer №1

Answer №2

Recommendation

Answer №3

Similar questions

Extracting textual information from Wikipedia through iframes?

Tips for managing CSS/style conflicts in JavaScript/AngularJS applications

A JavaScript right-click menu that updates a variable when clicked

What would be the JavaScript counterpart to python's .text function?

Guide on how to beautify HTML and generate output files in the identical directory as the current one

Issue with React form not appearing on web browser

Interact with various div elements bearing the same class name through mouse movements

Using Vuetify to send a parameter from a select option to a method as a parameter

The requested file cannot be accessed using XMLHttpRequest.open url

Angular Square Grid Design

What methods can I use to streamline integration with minimal lines of code?

JavaScript code often contains dates that are formatted in various ways

What is the correct approach for detecting object collisions in Phaser 3?

Modify the location of the input using jQuery

What is the best way to showcase an array's contents on a form?

Combining two fetching objects to deliver a response to a React application using Node.js and MongoDB

Utilizing the default validation in Bootstrap 4 to ensure proper email format in form submissions

Unable to retrieve variable declared externally from Switch Statement

What is the best way to extract a value from two different HTML identifiers?

Getting the specific nested array of objects element using filter in Angular - demystified!