var str = "This is a test. Here is word1 and here is word2, which may or may not exist.";
var matches = str.match( /word1|word2/g );
//-> ["word1", "word2"]

String.prototype.match will run a regex against the string and find all matching hits. In this case we use alternation to allow the regex to match either word1 or word2.

You need to apply the global flag to the regex so that match() will find all results.

If you care about matching only on word boundaries, use /\b(?:word1|word2)\b/g.

Returns true when all parts (divided by , or ' ') of a searchString occur in text. Otherwise false is returned.

filter(text, searchString) {
    const regexStr = '(?=.*' + searchString.split(/\,|\s/).join(')(?=.*') + ')';
    const searchRegEx = new RegExp(regexStr, 'gi');
    return text.match(searchRegEx) !== null;
}

You can achieve this will lookahead assertions

^(?=.*\bmeat\b)(?=.*\bpasta\b)(?=.*\bdinner\b).+

See it here on Regexr

(?=.*\bmeat\b) is a positive lookahead assertion, that ensures that \bmeat\b is somewhere in the string. Same for the other keywords and the .+ is then actually matching the whole string, but only if the assertions are true.

But it will match also on "dinner meat Foobar pasta"

You can use

(?=.*test)(?=.*long)

Source: MySQL SELECT LIKE or REGEXP to match multiple words in one record

You forgot to allow for a space between your "words":

\b\D*?\b(?:\s+\b\D*?\b)+
           ^^^

There are a number of other problems I can see:

I'm also rather suspicious of your definition of "word". Any non-numeric character also includes punctuation and whitespace. That's probably not what you really mean. You might want to try defining word like this instead: [^\d\s]+. This still allows words to contain punctuation, but it disallows both numerals and whitespace.

There is a problem with your usage of word boundaries - if a word can consist of punctuation then words beginning or ending on punctuation won't have a word boundary so your regular expression will miss them.

Are you searching for a string that contains at least two "words", and possibly also some numbers? Or must the string consist only of "words" and no numbers at all anywhere in the string? Currently your regular expression is looking for two consecutive "words" but in general they might not be consecutive.

For the situation you're describing, you don't even need regular expressions. If you split the search string on spaces; you can check every one of the words to match is contained within the array of search words.

function matchesAllWords(searchWords, inputString) {
  var wordsToMatch = inputString.toLowerCase().split(' ');

  return wordsToMatch.every(
    word => searchWords.indexOf(word) >= 0);
}

In the snippet below, typing in the input causes a recalculation of the searchWords. The matching li elements are then given the .match class to highlight them.

function updateClasses(e) {
  var searchWords = e.target.value.toLowerCase().split(' ');

  listItems.forEach(listItem => listItem.classList.remove('match'));

  listItems.filter(
      listItem =>
      matchesAllWords(searchWords, listItem.innerText))
    .forEach(
      matchingListItem =>
      matchingListItem.classList.add('match'));
}

function matchesAllWords(searchWords, inputString) {
  var wordsToMatch = inputString.toLowerCase().split(' ');
  
  return wordsToMatch.every(
    word => searchWords.indexOf(word) >= 0);
}

function searchProperties(e) {
  var searchWords = e.target.value.toLowerCase().split(' ');

  for (var property in propertiesToSearch) {
    if (matchesAllWords(searchWords, property)) {
      console.log(property, propertiesToSearch[property]);
    }
  }
}

var propertiesToSearch = {
  "red apples": 1,
  "juicy fruit": 2
};

listItems = [].slice.call(
  document.getElementById('matches').querySelectorAll('li')
);

document.getElementById('search').addEventListener('keyup', updateClasses);
document.getElementById('search').addEventListener('keyup', searchProperties);

.match {
  color: green;
}

<label for="search">
  Search:
</label>
<input type="text" name="search" id="search" />

<ul id="matches">
  <li>red apples</li>
  <li>juicy fruits</li>
</ul>

Update To use this kind of implementation to search for a property, use a for .. in loop like below. Again, see the snippet for this working in context.

function searchProperties(e) {
  var searchWords = e.target.value.toLowerCase().split(' ');

  for (var property in propertiesToSearch) {
    if (matchesAllWords(searchWords, property)) {
      console.log(property, propertiesToSearch[property]);
    }
  }
}

var propertiesToSearch = {
  "red apples": 1,
  "juicy fruit": 2
};

You can use this regex with optional space matching:

var reg = /\babc ?def ?ghi\b/i;

\b is used for word boundary.

Or you can strip all whitespace beforehand from input and match the string as:

var m = input.replace(/\s+/g, "").match(/\babcdefghi\b/i);