Find the length of the longest string in an array

Map strings to lengths and take the maximum.

JavaScript Version 1.0.0 · MIT · .md

function longestLength(words) { return Math.max(0, ...words.map(word => word.length)); }

Input & expected output

[
  "[email protected]",
  "[email protected]",
  "[email protected]"
]

15

The edge case

[]

0

Know the limits

• Starting from 0 makes an empty array return 0; the original returned -Infinity.
• Lengths are UTF-16 code units.

The function above is the implementation used by the lab. The lab validates JSON types and caps size before execution; include equivalent validation when accepting untrusted input in your application.

Keep exploring

• Clone an array — Create a new array without copying the objects inside it.
• Remove duplicate values — Keep the first occurrence of each value, in its original order.
• Flatten a nested array — Turn a nested array into one sequence of values.