Expose methods as functions (bound methods)

[Treora]

Currently, importing a single function from a module (in ES6) like so:

import { getDomain } from 'tldjs';
getDomain(url)

fails with:

TypeError: Cannot read property 'isValid' of undefined
    at getDomain (.....)

This happens because getDomain relies on this being the tldjs object.

To fix this, could you perhaps expose the methods as independent functions?

[thom4parisot]

@Treora yeah it would be totally doable but it would imply to possibly break the API. Which is not a bad thing considering it is more a functional library rather than a class, really.

I see a few changes to operate:

• this.validHosts is bound to the class instance, and is used by #getDomain and #isValid;
• #getRulesForTld is used by #getDomain; it relies on this.rules to operate;
• static methods can be taken out so that's an easy job.

Maybe the easiest move would be to:

1. make everything as an independent function (some with more parameters)
2. tldjs exports an object with partially applied rules (for convenience)

I suppose if people want to feed it different rules, they would have to do some more work but well, it can be documented or made easier for them if needed.

What do you think?

[Treora]

You could opt to keep the API exactly the same if desired: you could just pass each function through bind, so that its this will always be the tld instance.

If you wish to clean things up though, I would stop having rules and validHosts as global state of the module. Partially applied rules is indeed one way to go, or you could let the user 'recreate the module' with custom rules, for example like so:

function factory(rules, validHosts) {
    function getDomain(url) {
       ...rules[...url...]...
    }
    ...
    return {
        getDomain: getDomain,
        getSubdomain: getSubdomain,
        ...
        withCustomRules: factory
    }
}
module.exports = factory(require('rules.json'), [])

I have no strong opinion either way.

[thom4parisot]

@Treora, feel free to have a look at #86 to see if it fits your need. I had to change the way valid hosts were assigned as I don't think it is possible to track a mutated bound array.

[Treora]

Awesome. I almost feel guilty about having triggered such a code reorganisation effort with my tiny complaint. Thanks for your noble labour!

[thom4parisot]

No problem, it was some kind of distraction for the mind :-)