Emulating SQL LIKE in JavaScript

Question

How can I emulate the SQL keyword LIKE in JavaScript?

For those of you who don't know what LIKE is, it's a very simple regex which only supports the wildcards %, which matches 0 or more characters, and _ which matches exactly one character.

However, it's not just possible to do something like:

var match = new RegEx(likeExpr.replace("%", ".*").replace("_", ".")).exec(str) != null;

...because the pattern might contain dots, stars and any other special regex characters.

Answer 1

Here's a function I use, based on PHP's preg_quote function:

function regex_quote(str) {
  return str.replace(new RegExp("([\\.\\\\\\+\\*\\?\\[\\^\\]\\$\\(\\)\\{\\}\\=\\!\\<\\>\\|\\:\\-])", "g"), "\\$1");
}

So your line would now be:

var match = new RegEx(regex_quote(likeExpr).replace("%", ".*").replace("_", ".")).exec(str) != null;