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README.md

ArgSnip

Snips arguments off of callback functions, for simpler code and cleaner APIs.

Build Status

Installation

In your project folder, type:

npm install argsnip

Usage

Whenever you have code that looks like this, just to trim off unnecessary arguments from your callback:

db.query(query, function(err, result, code, meta) {
    callback(err, result);
}

Just snip the args!

var argSnip = require('argsnip');
db.query(query, argSnip(2, callback));

But what if you want just the 'err' and 'code' arguments?

db.query(query, argSnip([0, 2], callback));

How about the same two, in reverse order?

db.query(query, argSnip([2, 0], callback));

What if we want all arguments except the first one?

db.query(query, argSnip(1, null, callback));

What if we want to skip the first one, then take the next two arguments?

db.query(query, argSnip(1, 2, callback));
// OR:
db.query(query, argSnip([1, 2], callback));

Details

ArgSnip will save you from using countless wrapper functions to sanitize your callback arguments by letting you send just a slice or cheery-pick of the original arguments to the specified function. Here's what it looks like:

argSnip([start], args, callback)

  • start: An optional index at which to start grabbing arguments. If omitted, it's 0.

  • args: The number of arguments from the 'start' index that should be sent to the callback, OR an array specifying the index of each argument to be sent to the callback, in the order they should be arranged in. Null to take all arguments after the start index.

  • callback: The function to call with reduced arguments.

Returns

Your callback function. But when it's called, only the specified subset of arguments will be passed into it. The 'this' context will not be affected. Any arguments argSnip expects, but doesn't see at call time, will be passed as undefined.

Example:

var cb = argSnip([0, 9, 1], function(a, b, c) {
    // a is 0, b is undefined, c is 1.
});
cb(0, 1, 2);

License

ArgSnip is distributed under the MIT license.

Credits

ArgSnip was created by Tom Frost in 2012. Because screw writing callback wrappers.

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