function goodEmptyCheck(value) { Object.keys(value).length === 0 && value.constructor === Object; // 👈 constructor check } goodEmptyCheck(new String()); // false ✅ goodEmptyCheck(new Number()); // false ✅ goodEmptyCheck(new Boolean()); // false ✅ goodEmptyCheck(new Arra...
#Testing empty check on other values Alright, let's test our method on some values and see what we get 🧪 functionisEmptyObject(value){returnObject.keys(value).length===0&&value.constructor===Object;} Looks good so far, it returnsfalsefor non-objects. ...
//TypeError:CannotcovertundefinedornullotobjectgoodEmptyCheck(undefined);goodEmptyCheck(null);为了解决这个问题，可以加一个存在性判断,解决错误抛出 functiongoodEmptyCheck(value){value&&Object.keys(value).length===0&&value.constructor===Object;//?constructorcheck}二、旧浏览器中使用Object.prototy...
With the constructor, you can check if an object is aDate: Example (myDate.constructor=== Date); Try it Yourself » All Together typeof"John"// Returns "string" typeof("John"+"Doe")// Returns "string" typeof3.14// Returns "number" ...
varperson1={lastName:"Smith",firstName:"Tom"};varo1=Object.create(null);// an empty object with no slots 如果Slot 的name 是合法的JS 标识符,则Slot可表示属性,方法,或键值对。如果名称含有一些特殊字符如空格,则Slot代表键值对,是一种映射元素,如下: ...
[t]:t.match(P)||[]).length;while(n--)delete r[t[n]]}(void 0===t||S.isEmptyObject(r))&&(e.nodeType?e[this.expando]=void 0:delete e[this.expando])}},hasData:function(e){var t=e[this.expando];return void 0!==t&&!S.isEmptyObject(t)}};var Y=new G,Q=new G,J=/^...
JavaScript will actually create anError objectwith two properties:nameandmessage. The throw Statement Thethrowstatement allows you to create a custom error. Technically you canthrow an exception (throw an error). The exception can be a JavaScriptString, aNumber, aBooleanor anObject: ...
Delete an empty bucket.parameters:name {String} bucket name If bucket is not empty, will throw BucketNotEmptyError. If bucket is not exists, will throw NoSuchBucketError. [options] {Object} optional parameters [timeout] {Number} the operation timeout ...
if (!$.isEmptyObject(node.data)) { // alert("custom node data: " + JSON.stringify(node.data)); } }, beforeActivate: function (event, data) { logEvent(event, data, "current state=" + data.node.isActive()); // return false to prevent default behavior (i.e. activation) ...
checkbok的事件 执行先后 实例;表单验证 3、前端组件 实际就是别人写好了模板,样式,做个了结,在后面的项目部分,或使用这些个前端组件,进行快速的前端开发 几个比较出名的组件 easyui jqueryui bootstrap 组件的补充内容 3.1、响应式 @media 根据web界面的长框等因素使用不同的样式。即自适应 ...