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Mixins

Taking the idea of inheritance by property copying a step further, consider this this mixin implementation.

Instead of copying from one object, you can copy from any number of objects.

The implementation is pretty simple - just loop through arguments and copy every property of every object passed to the function.

function mixInThese() {
  var arg, prop, child = {};
  for (arg = 0; arg < arguments.length; arg++) {
    for (prop in arguments[arg]) {
      child[prop] = arguments[arg][prop];
    }
  }
  return child;
}

Here's how to use it. Pass any number of objects and you and up with a new object that has the properties of them all.

var cake = mixInThese(
 {eggs: 2, large: true}, 
 {butter: 1, salted: true}, 
 {flour: "3 cups"},
 {sugar: "sure!"}
);

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This entry was posted on Tuesday, September 15th, 2009 and is filed under Code reuse patterns. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.

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