将数组转换为逗号分隔语法正确的句子

Question

If I have an array in Javascript that looks like

searchComponents = ['element1', 'element2', 'element3'];

What is the necessary logic to turn it into a sentence like:

"element1, element2, and element3"

Likewise, if there are only two elements it should read like:

"element1 and element2"

and so on and so forth. I am stuck.

Answer 1

One easy solution:

function arrayToSentence (arr) {
    var last = arr.pop();
    return arr.join(', ') + ' and ' + last;
}

console.log(arrayToSentence(['one','two','three']));

JS Fiddle demo .

And a slightly more complex/ridiculous solution (because who doesn't like silly, occasionally...):

function arrayToSentence (arr) {
    var len = arr.length;
    return arr.reduce(function(a,b,c){
        return a + (c - 1 === length ? ', ' : ' and ') + b;
    });
}

console.log(arrayToSentence(['one','two','three']));

JS Fiddle demo .

References:

• Array.prototype.join() .
• Array.prototype.pop() .
• Array.prototype.reduce() .

Answer 2

function toSentence(arr) {
  return arr.slice(0, -2).join(', ') + 
    (arr.slice(0, -2).length ? ', ' : '') + 
    arr.slice(-2).join(' and ');
}

usage

toSentence([1])

1

toSentence([1, 2])

1 and 2

toSentence([1, 2, 3])

1, 2 and 3

toSentence([1, 2, 3, 4, 5, 6])

1, 2, 3, 4, 5 and 6

Answer 3

Try my compound-subject library:

https://github.com/adamshaylor/compound-subject

It includes controls over what character to delimit with (eg commas versus semicolons) as well as whether to delimit all the subjects (ie the “Oxford comma”).

Answer 4

More ES6/7 version without mutation:

function buildSentence (arr = []) {
  if (arr.length === 0) {
    return '';
  }

  if (arr.length === 1) {
    return arr[0];
  }

  const newArr = [...arr];
  const last = newArr.pop();    
  return newArr.join(', ') + ' and ' + last;
}
buildSentence([]);
buildSentence(['a']);
buildSentence(['a', 'b']);
buildSentence(['a', 'b', 'c']);

Answer 5

Here's a one liner:

 const arrayToSentence = (a) => [a.slice(0, -1).join(', '), a.pop()].filter(w => w !== '').join(' and '); console.log(arrayToSentence(['foo', 'bar', 'baz'])); console.log(arrayToSentence(['foo', 'bar'])); console.log(arrayToSentence(['foo'])); console.log(arrayToSentence([])); 

Answer 6

How's this...

function parseArray(arr) {
    var s=arr.toString();
    var c=s.lastIndexOf(",");
    if(c!=-1) s=(s.substr(0,c)+" and "+s.substr(c+1)).replace(/,/g,", ");
return s[0].toUpperCase()+s.substr(1)+".";
}

console.log(parseArray(["one", "two","three","four","five"]));
console.log(parseArray(["one", "two"]));
console.log(parseArray(["one"]));

Output is:

One, two, three, four and five.
One and two.
One.

Grammatically correct?

Answer 7

Here's a typed version that utilizes lodash functions:

import { concat, first, join, last, slice } from 'lodash'

function joinOxford (list: string[]): string {
  switch (list.length) {
  case 1: return first(list)
  case 1: return `${first(list)} and ${last(list)}`
  default: return join(concat(slice(list, 0, -1), [`and ${last(list)}`]), ', ')
  }
}

Usage:

joinOxford([foo])
// => foo

joinOxford([foo, bar])
// => foo and bar

joinOxford([foo, bar, baz])
// => foo, bar, and baz

joinOxford([foo, bar, baz, qux, quux, quuz])
// => foo, bar, baz, qux, quux, and quuz