Show HN: Xtypejs – Efficient data-validating pseudo types for JavaScript | Hacker News Reader

Show HN: Xtypejs – Efficient data-validating pseudo types for JavaScript

github.com

10 pointslucono6 comments

When I first saw the readme, I did a double-take at this:

    xtype(5)      === 'positive_integer';    // Value is number, positive and integer
    xtype(5)      === 'int+';               // 'int+' is same as 'positive_integer'

Unless there's some new ES6 magic I haven't heard about, Javascript does NOT permit operator overloading, so it should be impossible for an object to be === to more than one distinct string!

Looking more closely, the library seems to be quite useful, has a test suite, and the real syntax is xtype.is(5, 'int+'). But if that's the case, just say that! Don't pass off some nonworking pseudocode as real JS code in your readme! There's a saying "where there's smoke, there's fire," and if there's this egregious a deception in your documentation, it makes me hesitant to depend on the library!

There is no pseudo-code in the documentation. All of the documentation code executes as documented.

The library works with type names in two naming modes - default and compact. The default name scheme uses the full type names, such as 'positive_integer', while the compact name scheme uses compact names, such as 'int+' for 'positive_integer'.

You can only be in one mode or the other at any one time. You can switch between the two using the xtype.setOptions method:

    xtype(5);    // 'positive_integer'
    
    // Switch to compact name scheme:
    xtype.setOptions({nameScheme:'compact'});
    
    xtype(5);    // 'int+'

See this jsbin I've made for this specific piece of code - http://jsbin.com/kixuko/1/edit?html,js,console.

And the documentation for switching between the default and compact name schemes - https://github.com/lucono/xtypejs/blob/master/docs/Usage.md#....

I saw you updated the readme, thanks for that! In its previous state, it was much less clear: https://github.com/lucono/xtypejs/commit/4f9b631e2bd8cddb7be...

Again, I think it's a great library, and it's great to see you actively improving it - I was just offering some constructive criticism!

Constructive criticism is very welcome. I updated the docs to better highlight the compact naming scheme switch. Definitely appreciate the feedback.

This looks incredibly useful and I appreciate the focus on performance. I often avoid writing helpers for type checking edge cases due to performance concerns, but you've done the hard work for me. Thank you.

Thanks. I developed and used it as a utility in a bigger library that worked heavily with types, but later exported it to its own project so I could share it, after I realized how useful it was, even stand-alone.

It is very highly optimized, as performance was of critical importance.

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