functionmyFunction(){varfruits=["Banana","Orange","Apple","Mango"];varx=document.getElementById("demo");x.innerHTML=Array.isArray(fruits);} 尝试一下 » 定义和用法 isArray() 方法用于判断一个对象是否为数组。 如果对象是数组返回 true,否则返回 false。
Vue Js Check Undefined Array,Object or Property: In Vue.js, you can check if an array or object or object property is undefined using the typeof operator.To check if an array is undefined, you can use the typeof operator to check if the variable holding the array is of type "...
isArray()方法用于判断一个对象是否为数组。 如果对象是数组,返回true,否则返回false。 浏览器支持 语法 Array.isArray(obj) 参数 技术细节 实例 1varfruits = ["Banana", "Orange", "Apple", "Mango"];2varperson ={3name: '张三',4age: '27'5};6console.log(Array.isArray(fruits));//true7console...
// function return if an element is found in the array, else falsefunctioncheckTrueExistsArray(array) {for(vark=0;k<array.length;k++) {if(array[k]) {returntrue;break;}}returnfalse;}vararrayVariable=[false,false,true,false,true];vararrayVariable1=[false,false,false,false,false];console....
if (isObjectA && isObjectB) { try { const isArrayA = Array.isArray(a) const isArrayB = Array.isArray(b) if (isArrayA && isArrayB) { return a.length === b.length && a.every((e, i) => { return looseEqual(e, b[i]) ...
CallCheckObjectCoercible(baseValue ).Let propertyNameString beToString(propertyNameValue ).If the ...
1. Use Object.keys Object.keys will return an array, which contains the property names of the object. If the length of the array is 0, then we know that the object is empty. function isEmpty(obj) { return **Object.keys(obj).length === 0**; } We can also check this using Objec...
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 you don't want it to throw aTypeError, you can add an extra check: letvalue;value// 👈 null and undefined check&&Object.keys(value).length===0&&value.constructor===Object;value=null;// nullvalue=undefined;// undefined Perfect, no error is thrown 😁 ...
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. ...