freeCodeCamp/curriculum/challenges/en/08-coding-interview-prep/rosetta-code/comma-quibbling.en.md

title, id, challengeType

title	id	challengeType
Comma quibbling	596e414344c3b2872167f0fe	5

Description

Comma quibbling is a task originally set by Eric Lippert in his blog.

Task:

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

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

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

[] # (No input words). ["ABC"] ["ABC", "DEF"] ["ABC", "DEF", "G", "H"]

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

Instructions

Tests

- text: <code>quibble</code> is a function.
  testString: 'assert(typeof quibble === ''function'', ''<code>quibble</code> is a function.'');'
- text: '<code>quibble(["ABC"])</code> should return a string.'
  testString: 'assert(typeof quibble(["ABC"]) === ''string'', ''<code>quibble(["ABC"])</code> should return a string.'');'
- text: '<code>quibble([])</code> should return "{}".'
  testString: 'assert.equal(quibble(testCases[0]), results[0], ''<code>quibble([])</code> should return "{}".'');'
- text: '<code>quibble(["ABC"])</code> should return "{ABC}".'
  testString: 'assert.equal(quibble(testCases[1]), results[1], ''<code>quibble(["ABC"])</code> should return "{ABC}".'');'
- text: '<code>quibble(["ABC", "DEF"])</code> should return "{ABC and DEF}".'
  testString: 'assert.equal(quibble(testCases[2]), results[2], ''<code>quibble(["ABC", "DEF"])</code> should return "{ABC and DEF}".'');'
- text: '<code>quibble(["ABC", "DEF", "G", "H"])</code> should return "{ABC,DEF,G and H}".'
  testString: 'assert.equal(quibble(testCases[3]), results[3], ''<code>quibble(["ABC", "DEF", "G", "H"])</code> should return "{ABC,DEF,G and H}".'');'

Challenge Seed

function quibble (words) {
  // Good luck!
  return true;
}

After Test

console.info('after the test');

Solution

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