freeCodeCamp/curriculum/challenges/chinese/02-javascript-algorithms-an.../basic-algorithm-scripting/truncate-a-string.md

2.1 KiB

id title challengeType forumTopicId dashedName
ac6993d51946422351508a41 截断字符串 5 16089 truncate-a-string

--description--

如果传入的字符串(第一个参数)的长度大于传入的值(第二个参数),请在这个位置截断它, 并在后面加上 ...,然后返回结果。

--hints--

truncateString("A-tisket a-tasket A green and yellow basket", 8) 应返回 A-tisket...

assert(
  truncateString('A-tisket a-tasket A green and yellow basket', 8) ===
    'A-tisket...'
);

truncateString("Peter Piper picked a peck of pickled peppers", 11) 应返回 Peter Piper...

assert(
  truncateString('Peter Piper picked a peck of pickled peppers', 11) ===
    'Peter Piper...'
);

truncateString("A-tisket a-tasket A green and yellow basket", "A-tisket a-tasket A green and yellow basket".length) 应返回 A-tisket a-tasket A green and yellow basket

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'
);

truncateString("A-tisket a-tasket A green and yellow basket", "A-tisket a-tasket A green and yellow basket".length + 2) 应返回 A-tisket a-tasket A green and yellow basket

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'
);

truncateString("A-", 1) 应返回字符串 A...

assert(truncateString('A-', 1) === 'A...');

truncateString("Absolutely Longer", 2) 应返回 Ab...

assert(truncateString('Absolutely Longer', 2) === 'Ab...');

--seed--

--seed-contents--

function truncateString(str, num) {
  return str;
}

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

--solutions--

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);