fnguard v0.6.6

fnguard

(c)Bumblehead MIT-license

fnguard provides something similar to an Erlang-style "function guard". Inside the function, the parameter types are specified and, at runtime, if one of the params is wrong, and error is thrown and with a message explaining which parameter failed and a stack trace started from the call to fnguard.

The functions used to test each value are made to be safe and logical. For example, the function used for 'isobj' and 'isnotobj' looks like this, so that null and other values don't pass the test.

isobj : o =>
  typeof o === 'object'
  && !spec.isarr(o)
  && !spec.isdate(o)
  && !spec.isnull(o)
  && !spec.isre(o);

Here's an example of its usage

gethtml = (session, config, templatename, dataarr) => {
  fnguard.isobj(session, config).isstr(templatename).isarr(dataarr);
  
  // continue
}

fnguard is useful when refactoring bigger javascript codebases for which you have no unit-tests. Or highly dynamic sources which are difficult to type check. Run the tests or look at the source code (small) to understand how it handles comparison.

A negation function prefixed with isnot is provided for each 'is' function, for example:

spec.isnotnum = function (n) {
  return !spec.isnum(n);
};

Todo:

• would be great if fnguard could use custom types (similar to how Erlang does this)

(The MIT License)

Copyright (c) Bumblehead chris@bumblehead.com

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

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