freeCodeCamp/curriculum/challenges/english/02-javascript-algorithms-and-data-structures/basic-algorithm-scripting/truncate-a-string.english.md

id, title, isRequired, challengeType

id	title	isRequired	challengeType
ac6993d51946422351508a41	Truncate a String	true	5

Description

Truncate a string (first argument) if it is longer than the given maximum string length (second argument). Return the truncated string with a ... ending. Remember to use Read-Search-Ask if you get stuck. Write your own code.

Instructions

Tests

tests:
  - text: '<code>truncateString("A-tisket a-tasket A green and yellow basket", 8)</code> should return "A-tisket...".'
    testString: 'assert(truncateString("A-tisket a-tasket A green and yellow basket", 8) === "A-tisket...", "<code>truncateString("A-tisket a-tasket A green and yellow basket", 8)</code> should return "A-tisket...".");'
  - text: '<code>truncateString("Peter Piper picked a peck of pickled peppers", 11)</code> should return "Peter Piper...".'
    testString: 'assert(truncateString("Peter Piper picked a peck of pickled peppers", 11) === "Peter Piper...", "<code>truncateString("Peter Piper picked a peck of pickled peppers", 11)</code> should return "Peter Piper...".");'
  - text: '<code>truncateString("A-tisket a-tasket A green and yellow basket", "A-tisket a-tasket A green and yellow basket".length)</code> should return "A-tisket a-tasket A green and yellow basket".'
    testString: 'assert(truncateString("A-tisket a-tasket A green and yellow basket", "A-tisket a-tasket A green and yellow basket".length) === "A-tisket a-tasket A green and yellow basket", "<code>truncateString("A-tisket a-tasket A green and yellow basket", "A-tisket a-tasket A green and yellow basket".length)</code> should return "A-tisket a-tasket A green and yellow basket".");'
  - text: '<code>truncateString("A-tisket a-tasket A green and yellow basket", "A-tisket a-tasket A green and yellow basket".length + 2)</code> should return "A-tisket a-tasket A green and yellow basket".'
    testString: 'assert(truncateString("A-tisket a-tasket A green and yellow basket", "A-tisket a-tasket A green and yellow basket".length + 2) === "A-tisket a-tasket A green and yellow basket", "<code>truncateString("A-tisket a-tasket A green and yellow basket", "A-tisket a-tasket A green and yellow basket".length + 2)</code> should return "A-tisket a-tasket A green and yellow basket".");'
  - text: '<code>truncateString("A-", 1)</code> should return "A...".'
    testString: 'assert(truncateString("A-", 1) === "A...", "<code>truncateString("A-", 1)</code> should return "A...".");'
  - text: '<code>truncateString("Absolutely Longer", 2)</code> should return "Ab...".'
    testString: 'assert(truncateString("Absolutely Longer", 2) === "Ab...", "<code>truncateString("Absolutely Longer", 2)</code> should return "Ab...".");'

Challenge Seed

function truncateString(str, num) {
  // Clear out that junk in your trunk
  return str;
}

truncateString("A-tisket a-tasket A green and yellow basket", 8);

Solution

function truncateString(str, num) {
  if (num >= str.length) {
    return str;
  }

  return str.slice(0, num) + '...';
}

truncateString("A-tisket a-tasket A green and yellow basket", 8);