js string 为空 js 判断为空 js if判断为空 js 判断 为空 js 判断是否为string js 判断变量为string js判断是否为string js 判断为空 sponse js判断object为空 js 判断对象为空 js判断数组为空 js判断数据为空 js判断图片为空 js判断cookie为空
function isEmpty(value) { if (value === null || value === undefined) { return true; } if (typeof value === 'string' && value.trim().length === 0) { return true; } if (Array.isArray(value) && value.length === 0) { return true; } if (typeof value === 'object' &&...
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1、字符串 在js中,字符串为空会有这么几种形式,"",null,undefined,如果在已知变量为空串的情况下可以直接采用if (string.length == 0)这种形式,今天总结一下常用的几种方法,方便下次查阅。 1.1、typeof | null | ''「推荐👉:兼容null、undefined 」 functionisEmpty(obj) {if(typeofobj ==='undefined'...
js判断字符串是否为空,多个空格也算为空 String.prototype.trim =function() {returnthis.replace(/(^\s*)|(\s*$)/g, ''); }functionisEmpty(obj) {if(typeofobj === "undefined" || obj ==null|| obj.trim() == "") {returntrue; }else{returnfalse; } }...
function isNotEmptyStr(strval) { if (typeof strval== 'string' && strval.length > 0) { return true } return false } 二:判断字符串为空: function isEmptyStr(strval) { if (strval== null ||strval == undefined|| strval=== '') { ...
.items = {} this.count = 0 this.lowestCount =0 } toString(){ if(this.isEmpty()){ return '' } let objString = `${this.items[this.lowestCount]}` for (let i = this.lowestCount +1 ;i<this.count;i++){ objString = `${objString},${this.items[i]}` } return objString } ...
StringformName=intent.getStringParam(AbilitySlice.PARAM_FORM_NAME_KEY); intdimension=intent.getIntParam(AbilitySlice.PARAM_FORM_DIMENSION_KEY, DEFAULT_DIMENSION_2X2); HiLog.info(TAG,"onCreateForm: formId="+ formId +",formName="+ formName); ...
String: "Gorilla and banana" Symbol: Symbol("name") (starting ES2015) Null: null Undefined: undefined. 和一个单独的Object 类型:{name: "Dmitri"}, ["apple", "orange"]。 根据ECMAScript规范,从6种原始类型中,undefined是一个特殊的值,它有自己的Undefin...
It defaults to no referrer (which reflects as the empty string). contentType affects the value read from document.contentType, as well as how the document is parsed: as HTML or as XML. Values that are not a HTML MIME type or an XML MIME type will throw. It defaults to "text/html"...