extend.js

/**
 * Extend for Aimeejs
 * From jQuery.extend@2.0.3
 * Homepage https://github.com/Aimeejs/extend
 */

var is = require('is');

function extend() {
    var options, name, src, copy, copyIsArray, clone,
        target = arguments[0] || {},
        i = 1,
        length = arguments.length,
        deep = false;

    // Handle a deep copy situation
    if ( typeof target === "boolean" ) {
        deep = target;
        target = arguments[1] || {};
        // skip the boolean and the target
        i = 2;
    }

    // Handle case when target is a string or something (possible in deep copy)
    if ( typeof target !== "object" && !is.function(target) ) {
        target = {};
    }

    // extend parent self if only one argument is passed
    if ( length === i ) {
        target = this;
        --i;
    }

    for ( ; i < length; i++ ) {
        // Only deal with non-null/undefined values
        if ( (options = arguments[ i ]) != null ) {
            // Extend the base object
            for ( name in options ) {
                src = target[ name ];
                copy = options[ name ];

                // Prevent never-ending loop
                if ( target === copy ) {
                    continue;
                }

                // Recurse if we're merging plain objects or arrays
                if ( deep && copy && ( is.plainObject(copy) || (copyIsArray = is.array(copy)) ) ) {
                    if ( copyIsArray ) {
                        copyIsArray = false;
                        clone = src && is.array(src) ? src : [];

                    } else {
                        clone = src && is.plainObject(src) ? src : {};
                    }

                    // Never move original objects, clone them
                    target[ name ] = extend( deep, clone, copy );

                // Don't bring in undefined values
                } else if ( copy !== undefined ) {
                    target[ name ] = copy;
                }
            }
        }
    }

    // Return the modified object
    return target;
};

module.exports = extend;