JavaScript Program to Remove Empty Strings from Array Without Loop

JavaScript Program to Remove Last Character from the String

Given an array with values and empty strings, our task is to remove empty strings from an array while keeping a record of the removed elements without using explicit loops.

Example:

Input: Array = ["hello", "", "world", "", "!", " "];
Output: Cleaned Array: [ 'hello', 'world', '!', ' ' ]   Removed Elements: [ '', '' ]

Below are the approaches to remove empty strings from the array while keeping a record Without Loop in JavaScript:

Table of Content

Using reduce
Using filter
Using flatMap

Using reduce

In this approach, we use reduce to iterate through the array, accumulate non-empty strings in one array, and collect removed elements in another array.

Example: The below code example uses reduce to remove empty strings from array

JavaScript

function removeEmptyStrings(arr) {
    return arr
        .reduce((acc, val) => {
            if (val !== '') {
                acc.cleanedArray.push(val);
            } else {
                acc.removedElements.push(val);
            }
            return acc;
        }, { cleanedArray: [], removedElements: [] });
}

let inputArray = ["hello", "", "world", "", "!", " "];
let result = removeEmptyStrings(inputArray);

console.log("Cleaned Array:", result.cleanedArray);
console.log("Removed Elements:", result.removedElements);

Output

Cleaned Array: [ 'hello', 'world', '!', ' ' ]
Removed Elements: [ '', '' ]

Time complexity: O(n)

Auxiliary Space: O(n)

Using filter

In this approach we use filter to create a cleaned array of non-empty strings and another filter to create an array of empty strings.

Example: The below code example is a practical implementation to remove empty strings from array using filter with map.

JavaScript

function removeStrings(arr) 
{
    const cleanedArray = arr
        .filter(val => val !== '');
    const removedElements = arr
        .filter(val => val === '');
    return { cleanedArray, removedElements };
}

let inputArray2 = ["hello", "", "world", "", "!", " "];
let result2 = removeStrings(inputArray2);

console.log("Cleaned Array:", result2.cleanedArray);
console.log("Removed Elements:", result2.removedElements);

Output

Cleaned Array: [ 'hello', 'world', '!', ' ' ]
Removed Elements: [ '', '' ]

Time Complexity: O(n)

Auxiliary Space: O(n)

Using flatMap

In this approach, we use flatMap to create a combined operation of filtering and mapping, where we can conditionally return values or empty arrays, effectively achieving the desired result.

Example: The below code example uses flatMap to remove empty strings from the array:

JavaScript

function removeEmptyStringsFlatMap(arr) {
    const cleanedArray = arr.flatMap(val => val !== '' ? [val] : []);
    const removedElements = arr.flatMap(val => val === '' ? [val] : []);
    return { cleanedArray, removedElements };
}

let inputArray3 = ["hello", "", "world", "", "!", " "];
let result3 = removeEmptyStringsFlatMap(inputArray3);

console.log("Cleaned Array:", result3.cleanedArray);
console.log("Removed Elements:", result3.removedElements);

Output

Cleaned Array: [ 'hello', 'world', '!', ' ' ]
Removed Elements: [ '', '' ]

Time Complexity: O(n)

Auxiliary Space: O(n)

Tags:

#JavaScript-Program #JavaScript #Web Technologies

JavaScript Program to Remove Last Character from the String

JavaScript Program to Remove Empty Strings from Array Without Loop

Using reduce

Using filter

Using flatMap

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