JavaScript: Remove elements from the end of an array until the passed function returns true

JavaScript fundamental (ES6 Syntax): Exercise-242 with Solution

Remove Elements from End Until Condition

Write a JavaScript program to remove elements from the end of an array until the passed function returns true. Returns the remaining elements of the array.

• Loop through the array, using Array.prototype.slice() to drop the last element of the array until the value returned from func is true.
• Return the remaining elements.

Sample Solution:

JavaScript Code:

//#Source https://bit.ly/2neWfJ2 
// Define a function 'dropRightWhile' to remove elements from the end of an array until a condition is met
const dropRightWhile = (arr, func) => {
  // Iterate over the array while its length is greater than 0 and the condition for the last element fails
  while (arr.length > 0 && !func(arr[arr.length - 1])) 
    // Remove the last element from the array
    arr = arr.slice(0, -1);
  // Return the modified array
  return arr;
};

// Test the 'dropRightWhile' function with an array and a condition function
console.log(dropRightWhile([1, 2, 3, 4], n => n < 3)); // Output: [1, 2]

Output:

[1,2]

Flowchart:

Live Demo:

See the Pen javascript-basic-exercise-242-1 by w3resource (@w3resource) on CodePen.

For more Practice: Solve these Related Problems:

• Write a JavaScript program that removes elements from the end of an array until a specified condition becomes true and returns the modified array.
• Write a JavaScript function that pops elements off an array in reverse order until a predicate function returns true.
• Write a JavaScript program that iterates backwards through an array, removing items until a test condition is satisfied.
• Write a JavaScript function that returns the truncated array after all trailing elements failing a condition are removed.

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