function isEmpty(value) { // 对于null也认为是空对象,返回true if (value == null) { return true; } // 对数组/类数组对象/字符串/Buffer/arguments对象,根据length属性进行判断 if (isArrayLike(value) && (isArray(value) || typeof value == 'string' || typeof value.splice == 'function' ...
functionparseEmailAddress(input:string|null|undefined):Result<string>{// 如果 input 为 null,undefined 或空字符串//(所有都是虚假的值),就直接返回。if(!input){return{success:false,error:"The email address cannot be empty."};}// 我们只检查 input 是否与模式匹配// <something> @ <something> ....
这是因为当使用number来索引时,JavaScript会将它转换成string然后再去索引对象。 也就是说用100(一个number)去索引等同于使用"100"(一个string)去索引,因此两者需要保持一致。 class Animal { name: string; } class Dog extends Animal { breed: string; }// 错误:使用’string’索引,有时会得到Animal! interf...
If it doesn’t see that the string can be "round-tripped", then it will fall back to the base primitive type. Copy // JustNumber is `number` here because TypeScript parses out `"1.0"`, but `String(Number("1.0"))` is `"1"` and doesn't match. type JustNumber = "1.0" ...
static emptyOrWhiteSpaceString(obj: string, paramName: string) { if (obj === null || obj === '' || obj === ' ') { throw new ServiceException(`${paramName} name is empty.`); } } 我从一个评审员那里得到了这个建议: if (!obj || !obj.trim()) 我明白他想要什么,但我不明白...
letisShow:boolean=false;// 布尔值letnum:number=1;// 数字letname:string="Tom";// 字符串letarr:number[]=[1,2,3];// 数组定义1letarr:Array<any>=[1,2,3];// 数组定义2:数组泛型letx:[string,number]=["Tom",21];// 元组,包含两个元素的数组。enumColor{red,blue,green};// 枚举letx...
The syntax to declare a function with optional parameter is as given below −function function_name (param1[:type], param2[:type], param3[:type]) Example: Optional ParametersOpen Compiler function disp_details(id:number,name:string,mail_id?:string) { console.log("ID:", id); console....
@IsString() @IsNotEmpty({message:'video_id 不能为空'}) video_id: string; @...
✖ subject may not be empty[subject-empty]✖ type may not be empty[type-empty]✖ found2problems,0warnings ⓘ Get help:https://github.com/conventional-changelog/commitlint/#what-is-commitlint husky>commit-msg hookfailed(add--no-verify to bypass) ...
TypeScript 3.2 makes narrowing easier by relaxing rules for what’s considered a discriminant property. Common properties of unions are now considered discriminants as long as they containsomesingleton type (e.g. a string literal,null, orundefined), and they contain no generics. ...