Type Checking in JavaScript

Re:Type Checking in JavaScript by annnnd on Wednesday November 06, 2013 @06:53AM (#6682218)

Agree with you 100%.

One could use this system for asserts though:

    assert(type.isObject({})));
    assert(type.isNumber(NaN)); // fails
    assert(type.isElement(document.createElement('div')));
    assert(type.isRegExp(/abc/);

This could increase readability (because it documents the data type expectations) and would also break on some errors as soon as possible.

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Re:Type Checking in JavaScript by ghiculescu on Wednesday November 06, 2013 @08:00AM (#6682441)

It's still a lot of code being run without real benefit. Use Typescript if you really want static types, write sufficient unit tests either way, and you don't need this.

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Re:Type Checking in JavaScript by rimo on Wednesday November 06, 2013 @08:42AM (#6682589)

Static types and unit tests don't solve or catch all problems. I'm thinking about event-driven messaging systems, which is pretty common in js; Static typing will not be of any help in that situation.

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Re:Type Checking in JavaScript by danbruc on Wednesday November 06, 2013 @10:42AM (#6683211)

Sufficiently advanced type systems can enforce an enormous range of constraints. You can for example create a type for trees enforcing that the tree must be balanced; code that would unbalance a tree will just not compile.

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Re:Type Checking in JavaScript by embwbam on Wednesday November 06, 2013 @09:20AM (#6682758)

You can use a different observer pattern sometimes that can be caught by static typing, like Signals

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Re:Type Checking in JavaScript by annnnd on Friday November 08, 2013 @02:34AM (#6694996)

Sure - and you can test types in your unit tests using the OP's technique. :)

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