--description--

<a href="https://rosettacode.org/wiki/Comma_quibbling" target="_blank" rel="noopener noreferrer nofollow">Comma quibbling</a> is a task originally set by Eric Lippert in his blog.

--instructions--

Write a function to generate a string output which is the concatenation of input words from a list/sequence where:

<ol> <li>An input of no words produces the output string of just the two brace characters (<code>"{}"</code>)</li> <li>An input of just one word, e.g. <code>["ABC"]</code>, produces the output string of the word inside the two braces, e.g. <code>"{ABC}"</code></li> <li>An input of two words, e.g. <code>["ABC", "DEF"]</code>, produces the output string of the two words inside the two braces with the words separated by the string <code>" and "</code>, e.g. <code>"{ABC and DEF}"</code></li> <li>An input of three or more words, e.g. <code>["ABC", "DEF", "G", "H"]</code>, produces the output string of all but the last word separated by <code>", "</code> with the last word separated by <code>" and "</code> and all within braces; e.g. <code>"{ABC, DEF, G and H}"</code></li> </ol>

Test your function with the following series of inputs showing your output here on this page:

<ul> <li>[] # (No input words).</li> <li>["ABC"]</li> <li>["ABC", "DEF"]</li> <li>["ABC", "DEF", "G", "H"]</li> </ul>

Note: Assume words are non-empty strings of uppercase characters for this task.

--before-each--

const testCases = [[], ["ABC"], ["ABC", "DEF"], ["ABC", "DEF", "G", "H"]];
const results = ["{}", "{ABC}", "{ABC and DEF}", "{ABC, DEF, G and H}"];

--hints--

quibble should be a function.

assert(typeof quibble === 'function');

quibble(["ABC"]) should return a string.

assert(typeof quibble(['ABC']) === 'string');

quibble([]) should return "{}".

assert.equal(quibble(testCases[0]), results[0]);

quibble(["ABC"]) should return "{ABC}".

assert.equal(quibble(testCases[1]), results[1]);

quibble(["ABC", "DEF"]) should return "{ABC and DEF}".

assert.equal(quibble(testCases[2]), results[2]);

quibble(["ABC", "DEF", "G", "H"]) should return "{ABC, DEF, G and H}".

assert.equal(quibble(testCases[3]), results[3]);

--seed--

--seed-contents--

function quibble(words) {

  return true;
}

--solutions--

function quibble(words) {
  return "{" +
    words.slice(0, words.length - 1).join(", ") +
   (words.length > 1 ? " and " : "") +
   (words[words.length - 1] || '') +
  "}";
}