Javascript: Search array to see if it contains part of string

Question

Using javascript (or Jquery) how would I compare a string of text to an array and return matching values?

For example if I have an array:

    var names = ["John", "Mary", "George"];

And I have a string:

   var sentence = "Did Mary go to the store today?";

I want to compare the string and the array and return the matching word, in this example "Mary".

I have searched and everything I have found seems to be comparing for a specific string. What I am looking for is matching PARTIALS.

Thanks!

Answer 1

To avoid Johnathon matching John, you'll want to build a regular expression:

var names = ["John", "Mary", "George"];
var regex = new RegExp("(^|[^a-zA-Z0-9])(" + names.join("|") + ")([^a-zA-Z0-9]|$)", "g");

regex.test("Did Johnathon go to the store today?"); // false
regex.test("Did John go to the store today?");      // true

You want to match the name if the name is at the beginning of the string or a non alpha numeric character precedes it (^|[^a-zA-Z0-9]), AND if the name is at the end of the string or a non alpha numeric character succeeds it ([^a-zA-Z0-9]|$). Hence the two captures before and after the list of names.

To collect the names:

var matches = [];
var sentence = "Did John or Mary go to the store today?";

sentence.replace(regex, function(match, $1, $2, $3) {
     matches.push($2);
});

console.log(matches);

And a quick reusable function:

function getMatchingWords(words, s) {
    var matches = [],
        regex = new RegExp("(^|[^a-zA-Z0-9])(" + words.join("|") + ")([^a-zA-Z0-9]|$)", "g");

    s.replace(regex, function(match, $1, $2, $3) {
        matches.push($2);
    });

    return matches;
}

var matches = getMatchingWords(["John", "Mary", "Billy"], "Did John or Mary go to the store today?");