将JavaScript代码迁移到具有String.prototype扩展名的node.js模块

Question

I'm trying to migrate Crockfords TDOP based parser to Node.js, as I want to use it as a base for my own parser.

In his code he extends the String object with a new method called "tokens":

String.prototype.tokens = function (prefix, suffix) {
[...]

Source: https://github.com/douglascrockford/TDOP/blob/master/tokens.js#L25

This method gets called by his parser later:

[...]

return function (source) {
    tokens = source.tokens('=<>!+-*&|/%^', '=<>&|');
    token_nr = 0;
    new_scope();
    advance();
    var s = statements();
    advance("(end)");
    scope.pop();
    return s;
};

[...]

Source: https://github.com/douglascrockford/TDOP/blob/master/parse.js#L520

In the browser version he simply loads all those files which seem to be added to the global scope so all works fine:

https://github.com/douglascrockford/TDOP/blob/master/index.html#L58

I'm now trying to get this to work in Node. For that I started stripping out the stuff which is browser based and read a sample file from filesystem.

It seems to do something up to the point where the String.tokens method gets called, in there I get 'my string' has no method 'tokens' . In my limited understanding of scopes I suspect that this is because node seems to create its own "global" scope for each module. My big question now is how can I extend the String object in a way that this will work out? I tried defining this method in many different scopes in my sample code but I couldn't get a single one of them to work. My idea is to have the parse method as a module and then assign String.prototype.tokens == mymodule.tokens from that file.

Is this the right approach and if so, where the heck do I have to define the String.prototype.tokens method that my code will be able to find it?

I've created a github repository with my node code, pull requests are welcome ;)

https://github.com/ktk/js-scope-test/blob/master/node.js

Answer 1

This did work all the time as Bubbles pointed out. I forgot to call toString() on the Buffer object I got from fs.readFile...

Sorry & thanks for the hints.