How To Extend Ejson To Serialize Regex For Meteor Client-server Interactions?

I have an arbitrary (E)JSON that gets created and sent over the wire from client to server in my Meteor app. It uses RegExp objects to zero-in on results: # on the client selector

Solution 1:

After reviewing this HowTo and the Meteor EJSON Docs, we may serialize RegEx using the EJSON.addType method.

Extend RegExp - Provide RegExp with the methods EJSON.addType requires for implementation.

RegExp::options = ->
  opts = []
  opts.push 'g'if @global
  opts.push 'i'if @ignoreCase
  opts.push 'm'if @multiline
  return opts.join('')

RegExp::clone = ->self = @
  return new RegExp(self.source, self.options())

RegExp::equals = (other) ->self = @
  if other isnt instanceOf RegExp
    returnfalsereturn EJSON.stringify(self) is EJSON.stringify(other)

RegExp::typeName = ->return"RegExp"

RegExp::toJSONValue = ->self = @
  return {
    'regex': self.source
    'options': self.options()
  }

Call EJSON.addType - Do this anywhere. It's best to make it available to client AND server though. This is going to deserialize the object defined in toJSONValue above.

EJSON.addType"RegExp", (value) ->
  returnnewRegExp(value['regex'], value['options'])

Test In Your Console - Don't take my word for it. See for yourself.

> o = EJSON.stringify(/^Mooo/ig)
"{"$type":"RegExp","$value":{"regex":"^Mooo","options":"ig"}}"
> EJSON.parse(o)
/^Mooo/gi

And there you have a RegExp being serialized and parsed on client and server, able to be passed in over the wire, saved in a Session, and even possibly stored in a Collection of queries!

EDIT to addess IE10+ Error: Assignment to read-only properties is not allowed in strict mode Courtesy of @Tim Fletcher in the comments

import { EJSON } from'meteor/ejson';

functiongetOptions(self) {
  const opts = [];
  if (self.global) opts.push('g');
  if (self.ignoreCase) opts.push('i');
  if (self.multiline) opts.push('m');
  return opts.join('');
}

RegExp.prototype.clone = functionclone() {
  returnnewRegExp(this.source, getOptions(this));
};

RegExp.prototype.equals = functionequals(other) {
  if (!(other instanceofRegExp)) returnfalse;
  returnEJSON.stringify(this) === EJSON.stringify(other);
};

RegExp.prototype.typeName = functiontypeName() {
  return'RegExp';
};

RegExp.prototype.toJSONValue = functiontoJSONValue() {
  return { regex: this.source, options: getOptions(this) };
};

EJSON.addType('RegExp', value =>newRegExp(value.regex, value.options));

Solution 2:

There is a far simpler solution: stringify your RegExp via .toString(), send it to the server and then parse it back to RegExp.