Javascript comma list but has an and at the last one

Question

I am trying to create a function that will take a list of words -- and covert it into a sentence like this.

jsfiddle

http://jsfiddle.net/0ht35rpb/107/

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Answer 1

The function you have commented out seems to be right, except that it's using some property off this rather than the parameter passed to it.

Adjusting that, you get this:

const grammarCheck = function(vals) {
  return [ vals.slice(0, -1).join(", "), vals.slice(-1)[0] ]
         .join(vals.length < 2 ? "" : " and ");
}
grammarCheck(['foo']); //=> 'foo'
grammarCheck(['foo', 'bar']); //=> 'foo and bar'
grammarCheck(['foo', 'bar', 'baz']); //=> 'foo, bar and baz'
grammarCheck(['foo', 'bar', 'baz', 'qux']); //=> 'foo, bar, baz and qux'

Obviously, you could alter this a bit if you want the Oxford comma.