What is the best way to access the element before and after a specific element in an array using JavaScript?

Question

What is the best way to access the element before and after a specific element in an array using JavaScript?

I need to create a function that accepts a string input, searches for its match in an array, and then returns the previous and next elements in the array.

const array = [
      "11111",
      "22222",
      "343245",
      "5455",
      "34999",
      "34555",
    ];

When a user enters a random number, the function will determine the previous and next elements based on that input.

For instance, if the user inputs: 3499 The function will output: The previous element is 5455 and the next element is 34555.

javascript arrays

Answer 1

Answer №1

Implement the Array#indexOf method to locate the position of a specific element within an array, and then retrieve neighboring elements based on this position.

var array = [
  "apple",
  "banana",
  "orange",
  "pear",
  "grape",
  "kiwi",
];

var fruit = "pear";

var idx = array.indexOf(fruit);

console.log('Next fruit:', array[idx + 1])
console.log('Previous fruit:', array[idx - 1])

Answer 2

Implement the Array#indexOf method to locate the position of a specific element within an array, and then retrieve neighboring elements based on this position.

var array = [
  "apple",
  "banana",
  "orange",
  "pear",
  "grape",
  "kiwi",
];

var fruit = "pear";

var idx = array.indexOf(fruit);

console.log('Next fruit:', array[idx + 1])
console.log('Previous fruit:', array[idx - 1])

Answer 3

Answer №2

Utilizing the "indexOf" method:

function findNextNumber(value, array){
    const index = array.indexOf(value)
    if (index && index < array.length-1){
        return array[index+1]
    }
    return null
}

array = [5, 3, 7, 8, 1, 10];
value = 7;
console.log(findNextNumber(value, array)) //8

Alternatively, you can do it in a single line like this:

previous = array.find((_, i, arr) => value === arr[i + 1]);
next = array.find((_, i, arr) => value === arr[i - 1]);

Answer 4

Utilizing the "indexOf" method:

function findNextNumber(value, array){
    const index = array.indexOf(value)
    if (index && index < array.length-1){
        return array[index+1]
    }
    return null
}

array = [5, 3, 7, 8, 1, 10];
value = 7;
console.log(findNextNumber(value, array)) //8

Alternatively, you can do it in a single line like this:

previous = array.find((_, i, arr) => value === arr[i + 1]);
next = array.find((_, i, arr) => value === arr[i - 1]);

What is the best way to access the element before and after a specific element in an array using JavaScript?

Answer №1

Answer №2

Similar questions

Dispose the inputpicker filter after setting the value

Why isn't the login redirect script working without any errors or redirection?

Protractor test fails to retain variable's value

Elements that allow for asynchronous data submission without requiring a traditional submit button

What is the best way to loop through a JSON property without knowing if it is an array or not?

The latest changes in the MongoDB route and model may result in either data deletion or an error being thrown

What techniques can be used to optimize the SEO of HTML generated by JavaScript? How does React.js go about achieving this

Using Capybara for testing integration with asynchronous JavaScript

Aptana - Expose the Declaration

Change prompt-sync from require to import syntax

Recovering antiquated submission script in JavaScript

An advanced password checker that notifies the user of any spaces in their password

The Vue instance methods provide a way to access and manipulate formatted properties

Oops! Dropzone encountered an error because no URL was provided

Example using three.js showing issues with external resources failing to load on jsfiddle.net

Is it possible to export a constant from within a default function to a different file?

Ways to verify if an array is multi-dimensional

How can we automatically delete a message in DiscordJS after a certain amount of time has passed?

Exploring the concept of nested views in AngularJS's UI Router with multiple views integration

What is the best method for concealing a specific element on the screen using ReactJS?