JavaScript: Take any number of iterable objects or objects with a length property and returns the longest one

JavaScript fundamental (ES6 Syntax): Exercise-79 with Solution

Find Longest Iterable Object

Write a JavaScript program to take any number of iterable objects or objects with a length property and return the longest one.

• Use Array.prototype.reduce(), comparing the length of objects to find the longest one.
• If multiple objects have the same length, the first one will be returned.
• Returns undefined if no arguments are provided.

Sample Solution:

JavaScript Code:

//#Source https://bit.ly/2neWfJ2
// Define the function 'longestItem' to find the longest item among the provided values.
const longestItem = (...vals) =>
  // Spread the provided values into an array, sort the array by the length of each item in descending order,
  // and return the first (longest) item.
  [...vals].sort((a, b) => b.length - a.length)[0];

// Example usages:
console.log(longestItem('this', 'is', 'a', 'testcase')); // Outputs: 'testcase'
console.log(longestItem(...['a', 'ab', 'abc'])); // Outputs: 'abc'
console.log(longestItem(...['a', 'ab', 'abc'], 'abcd')); // Outputs: 'abcd'
console.log(longestItem([1, 2, 3], [1, 2], [1, 2, 3, 4, 5])); // Outputs: [1, 2, 3, 4, 5]
console.log(longestItem([1, 2, 3], 'foobar')); // Outputs: 'foobar'

Output:

testcase
abc
abcd
[1,2,3,4,5]
foobar

Visual Presentation:

Flowchart:

Live Demo:

See the Pen javascript-basic-exercise-79-1 by w3resource (@w3resource) on CodePen.

For more Practice: Solve these Related Problems:

• Write a JavaScript program that takes multiple iterable objects and returns the one with the greatest length.
• Write a JavaScript function that compares objects with a length property and returns the longest among them.
• Write a JavaScript program that iterates over various arrays or strings and identifies the longest one based on length.

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