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j2labs/arity_check.js

Created September 28, 2011 07:17
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  1. James Dennis revised this gist Sep 28, 2011. No changes.
  2. James Dennis created this gist Sep 28, 2011.
    17 changes: 17 additions & 0 deletions arity_check.js
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    Original file line number Diff line number Diff line change
    @@ -0,0 +1,17 @@
    exports.arity_decorator = function(fun) {
    function wrapped() {
    if(arguments.length != fun.length)
    throw new Error("Y U NO USE RIGHT?!")
    fun.apply(this, arguments)
    }
    return wrapped;
    }


    exports.foo = function(x, y) {
    console.log('X:' + x)
    console.log('Y:' + y)
    }


    exports.foo = exports.arity_decorator(exports.foo)
    14 changes: 14 additions & 0 deletions wrap_it.js
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    Original file line number Diff line number Diff line change
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    var arity_check = require("./arity_check");

    var bar = function(z) {
    console.log('Hi. Z:' + z);
    }
    bar = arity_check.arity_decorator(bar)



    arity_check.foo(3,4) // Works

    bar(5) // Works

    bar(5,6,7) // Throws error