@zkochan/async-regex-replace v0.2.0

async-regex-replace

node.js library for regex replacements using asynchronous callback functions

"All I needed" was a simple function to do string.replace(/regex/, callback_function) so that I could find some matches in a url and call my own custom function to return the value to be replaced back into the string. Sounds pretty easy right? It is, as long as your callback function is syncrhonous. :)

What happens if you need to call an asychronous function to determine the replacement value(s)? Perhaps you are using the match value to lookup a record in a database. In my case, I needed to perform DNS SRV record lookups to replace hostnames with the returned host:port combination.

Enter async-regex-replace

'use strict';
var arr = require('async-regex-replace');

arr.replace(/regex/g, "String with regex to replace", function(match, offset, original, callback) {
  setTimeout(function() {
    var replacement_value = match.split('').reverse().join('');
    var err = null;
    callback(err, replacement_value);
  }, 1000);
}, function(err, final_result) {
  if(err) { console.log("Error - " + err); }
  else {
    console.log(final_result);
    //> String with xeger to replace
  }
});

NOTE: In this particular example, the gratuitous use of setTimeout is just to demonstrate the asynchronous functionality in the replacement callback.