notes/node_modules/xtend/mutable.js

module.exports = extend

var hasOwnProperty = Object.prototype.hasOwnProperty;

function extend(target) {
    for (var i = 1; i < arguments.length; i++) {
        var source = arguments[i]

        for (var key in source) {
            if (hasOwnProperty.call(source, key)) {
                target[key] = source[key]
            }
        }
    }

    return target
}