jquery深度拷贝extend方法封装

应用场景

最近在搞微信小程序，这里面直接引入jquery的话会报错，但是项目用到了jq的extend方法，在这里抽离出这个函数，可以引入直接应用

抽离源码

var class2type = {};var toString = class2type.toString;var hasOwn = class2type.hasOwnProperty;var support = {};function extend() {    var src, copyIsArray, copy, name, options, clone,        target = arguments[0] || {},        i = 1,        length = arguments.length,        deep = false;    // Handle a deep copy situation    if ( typeof target === "boolean" ) {        deep = target;        // skip the boolean and the target        target = arguments[ i ] || {};        i++;    }    // Handle case when target is a string or something (possible in deep copy)    if ( typeof target !== "object" && !isFunction(target) ) {        target = {};    }    // extend jQuery itself if only one argument is passed    if ( i === length ) {        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 && ( isPlainObject(copy) || (copyIsArray = isArray(copy)) ) ) {                    if ( copyIsArray ) {                        copyIsArray = false;                        clone = src && isArray(src) ? src : [];                    } else {                        clone = src && isPlainObject(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;}// isPlainObject isFunction isArray isWindow typefunction isPlainObject( obj ) {    var key;    // Must be an Object.    // Because of IE, we also have to check the presence of the constructor property.    // Make sure that DOM nodes and window objects don't pass through, as well    if ( !obj || type(obj) !== "object" || obj.nodeType || isWindow( obj ) ) {        return false;    }    try {        // Not own constructor property must be Object        if ( obj.constructor &&            !hasOwn.call(obj, "constructor") &&            !hasOwn.call(obj.constructor.prototype, "isPrototypeOf") ) {            return false;        }    } catch ( e ) {        // IE8,9 Will throw exceptions on certain host objects #9897        return false;    }    // Support: IE<9    // Handle iteration over inherited properties before own properties.    if ( support.ownLast ) {        for ( key in obj ) {            return hasOwn.call( obj, key );        }    }    // Own properties are enumerated firstly, so to speed up,    // if last one is own, then all properties are own.    for ( key in obj ) {}    return key === undefined || hasOwn.call( obj, key );}function isFunction( obj ) {    return type(obj) === "function";}function isArray( obj ) {    return type(obj) === "array";}function isWindow( obj ) {    /* jshint eqeqeq: false */    return obj != null && obj == obj.window;}function type( obj ) {    if ( obj == null ) {        return obj + "";    }    return typeof obj === "object" || typeof obj === "function" ?        class2type[ toString.call(obj) ] || "object" :        typeof obj;}

应用示例

// 浅拷贝var result1 = extend({},      { name: "John", location: {city: "Boston",county:"USA"} },      { last: "Resig", location: {state: "MA",county:"China"} } ); console.log(result1);// 深拷贝var result2 = extend(true, {},      { name: "John", location: {city: "Boston",county:"USA"} },      { last: "Resig", location: {state: "MA",county:"China"} } ); console.log(result2);