function checkArray() { let emptyArray = []; let nonExistantArray = undefined; let fineArray = [1, 2, 3, 4, 5]; if(Array.isArray(emptyArray) && emptyArray.length) output = true; else output = false; document.querySelector('.output-empty').textContent = output; if(Array.isArray...
判断js 数组是否为 empty function isEmpty(obj) {for(varkeyinobj) {if(obj.hasOwnProperty(key))returnfalse; }returntrue; } var mycars =new Array();mycars[0] = ""; mycars[1] = ""; mycars[2] = ""; console.log(isEmpty(mycars)?'0':'1'), 资料来源: https://coderwall.com/p/...
AI代码解释 vararr=newArray();//输出为it is trueif(arr){console.log("it is true");}//输出为it is falseif(arr==true){console.log("it is true")}else{console.log("it is false");}Boolean(arr);//trueNumber(arr);//0Number(false);//0Number(true);//1...
functionisEmpty(a){if(a ==="")returntrue;//检验空字符串if(a ==="null")returntrue;//检验字符串类型的nullif(a ==="undefined")returntrue;//检验字符串类型的 undefinedif(!a && a !==0&& a !=="")returntrue;//检验 undefined 和 nullif(Array.prototype.isPrototypeOf(a) && a.length===...
//字符串非空判断functionisEmpty(obj){if(typeofobj=="undefined"||obj==null||obj==""){returntrue;}else{returnfalse;}} 2.Number类型(数字) (1).NaN:即非数值(Not a Number)。任何涉及NaN的操作都会返回NaN,NaN与任何值都不相等 代码语言:javascript ...
1. 用法:Array.filter(function(currentValue, indedx, arr), thisValue),其中,函数 function 为必须,数组中的每个元素都会执行这个函数。且如果返回值为 true,则该元素被保留; 函数的第一个参数 currentValue 也为必须,代表当前元素的值。 2.实例 ...
if (source[keys] && typeof source[keys] === 'object' ){ // 如果值是对象,就递归一下 targetobj[keys] = source[keys].constructor === array ? [] : {}; targetobj[keys] = deepclone(source[keys]); } else { // 如果不是,就直接赋值 ta...
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if (!env_v.IsEmpty() && env_v->IsArray()) { Local<Array> env_opt = Local<Array>::Cast(env_v); int envc = env_opt->Length(); CHECK_GT(envc + 1, 0); // Check for overflow. options.env = new char*[envc + 1]; // Heap allocated to detect errors. ...
function deepClone(obj ={}) { if (typeof obj !== 'object' || obj == {}) { return obj } let result if (obj instanceof Array) { result = [] } else { result = {} } for (let key in obj) { if (obj.hasOwnProperty(key)) { result[key] = deepClone(obj[key]) } } retu...