javascript: find all matched keywords in a string

Question

javascript: find all matched keywords in a string

I am trying to parse a big chunk of text to find all the matched keywords.

I have all the keywords in an array.

for eg:

var string = "hi, I need support for apple, android and nokia phones.";

var keywords = ['apple', 'nokia', 'android'];

for(i=0;i<keywords.length; i++){
    var match = string.match(keywords[i]);
    console.log(match);
}

This is kind of working for now. Just looking for a better and efficient solution.

javascript
performance
node.js

Answer 1

As @freakish said, combining them into one regexp is more efficient (given a decent regex engine). Of course that requires the matches not to overlap, if you need such you must test them one-by-one.

var match = string.match(new RegExp(keywords.join("|"), "g"));

Answer 2

One way; case-insensitive, whole words, no dups;

var string = "hi, I need support for apple, android and nokia phones.";

var keywords = ['apple', 'nokia', 'android'];
var results = [];
for(var i = 0; i < keywords.length; i++) {
    if ((new RegExp("\\b" + keywords[i] + "\\b", "i").test(keywords[i]))) {
        results.push(keywords[i]);
    }
}

alert( "contains: " + results );