https://www.codesolutionstuff.com/javascript-program-to-check-if-an-object-is-an-array/ Object.prototype 中的函数 toString 方法是确定对象是否是给定类的实例的最佳方法。 var数组列表 = [1,2,3]; 当我们在 JavaScript 中使用方法重载时,类型检查对象是最伟大的应用之一。假设我们有一个名为 greet 的方...
The [[Class]] property of the newly constructed object is set to “Array”. 于是利用这点,第三种方法登场了。 functionisArray(obj) { returnObject.prototype.toString.call(obj)==='[object Array]'; } call改变toString的this引用为待检测的对象,返回此对象的字符串表示,然后对比此字符串是否是'[object...
通过测试,使用如:obj instanceof Object的形式,只能是判断两种类型Object和Array,其中Boolean、Number、String可以判断,但是会返回false,如上面i和b变量;如果判断为null或者undefind会报Uncaught TypeError: Right-hand side of 'instanceof' is not an object这样的错误。 测试5: 直接通过Array.isArray(obj),javascri...
Checks if value is classified as an Array object. constarray=['🍝','🍜','🍲'];constnotArray='not array';_.isArray(array);// true_.isArray(notArray);// false Underscore Returns true if object is an Array. constarray=['🍝','🍜','🍲'];constnotArray='not array';_.isArr...
if(typeof(obj)=="object"){alert("是对象")}else{alert("不是")},但是javascript对于object定义的很宽泛,很多东西javascript都会认为是object,比如Date, String, Boolean, Number, Object, Function, Array, RegExp, Error。判断是不是array,可以使用isArray()来判断if(array.isArray()){"array是数组"}else...
Object.prototype.toString.call(variable) === '[object Array]'; 1. This guy is the slowest for trying to check for an Array. However, this is a one stop shop for any type you're looking for. However, since you're looking for an array, just use the fastest method above. ...
见下面的例子：function test2(){var a = [];var d = new Date();var o = {a:'test',b:'is',c:'ok'};var F = function(){}var of = new F();document.writeln(a instanceof Array);document.writeln(d instanceof Date);document.writeln(o instanceof Object);...
if (typeof param === 'object' && !isNaN(param.length)) { console.log('Congrats, you have an array!');} else { console.log('Bummer, not an array');} } // Works 成功 is_this_an_array(my_array);// Works, but is incorrect 成功了，但是不正确 is_this_an_array(my_...
JavaScript check if a value exists in an array of objects Simple example code. <!DOCTYPE html> <html> <body> <script> const arr = [{ id: 1, username: 'fred' }, { id: 2, username: 'bill' }, { id: 3, username: 'ted' }]; ...
If a number is supplied, delay is applied to both hide/show Object structure is: delay: { show: 500, hide: 100 } container string | false false Appends the tooltip to a specific element container: 'body' 注意! 可以针对单个工具提示指定单独的data属性。 标记 <a href="#" data-toggle="...