Deep object extend

deepExtend.coffee

# Check if obj is realy object.
# Note: returns 'false' for 'null'
#        (unlike 'typeof null' which returns 'object')
isObject = (obj) ->
    type = typeof obj
    type is 'function' || type is 'object' && !!obj

# Copy properties from source object
# to target object.
setProperties = (obj, source) ->
    for own prop, value of source
        if isObject(obj[prop]) and isObject(source[prop])
            deepExtend(obj[prop], value)
        else
            obj[prop] = value

# Define function to global scope
window.deepExtend = (obj) ->
    return obj if not isObject(obj)
    for i in [1...arguments.length] by 1
        setProperties(obj, arguments[i])
    obj

deepExtend.js

(function() {
    var isObject, setProperties;
  
    // Check if obj is realy object.
    // Note: returns 'false' for 'null'
    //       (unlike 'typeof null' which returns 'object')
    isObject = function(obj) {
        var type;
        type = typeof obj;
        return type === 'function' || type === 'object' && !!obj;
    };
  
    // Copy properties from source object
    // to target object.
    setProperties = function(obj, source) {
        var prop, value, _results;
        _results = [];
        for (prop in source) {
            if (!__hasProp.call(source, prop)) continue;
            value = source[prop];
            if (isObject(obj[prop]) && isObject(source[prop])) {
                _results.push(deepExtend(obj[prop], value));
            } else {
                _results.push(obj[prop] = value);
            }
        }
        return _results;
    };
  
    // Define function to global scope
    window.deepExtend = function(obj) {
        var i, _i, _ref;
        if (!isObject(obj)) {
            return obj;
        }
        for (i = _i = 1, _ref = arguments.length; _i < _ref; i = _i += 1) {
            setProperties(obj, arguments[i]);
        }
        return obj;
    };
})();

usage.js

//
// Usage
// deepExtend(source, obj1, [obj2], ... [objN])
//

var user = {
    first_name: "John",
    email: {
        main: '[email protected]'
    }
}

user = deepExtend(user, {last_name: 'Doe'}, {email:{work: '[email protected]'}})

// Will result into
{
    first_name: 'John',
    last_name: 'Doe',
    email: {
        main: '[email protected]',
        work: '[email protected]'
    }
}