functionprintUser(user:User){Object.keys(user).forEach((key)=>{// 不起作用!console.log(user[key]);// 出错信息如下:// Expression implicitly has an 'any' type because expression of type 'string' can't be used to index type 'User'.// No index signature with a parameter of type 'str...
Object.keys(obj).forEach((key) => { const parseKey = key as K; const value = obj[key]; result[key] = callback(parseKey, value); }); return result; } mapping({ name: '19Qingfeng', company: 'Tencent' }, (key, value) => { return key + value; }); 源码实现 看看它的源码本...
forEach的用法如下： var sarr=[1,2,3,4]; sarr.desc="hello"; sarr.forEach(value=>console.lo...
{ firstName: "Morty", lastName: "Smith", size: 6 }, { firstName: "Jerry", lastName: ...
使用Object.keys进行遍历并不能按照预期工作。这是因为Object.keys返回一个字符串数组,而不是包含所有键的联合类型。这是设计上的考虑,不会改变。 复制 functionprintUser(user:User){ Object.keys(user).forEach((key)=>{// 不起作用!console.log(user[key]);// 报错:属性“key”在类型“User”上不存在。
Update the TypeScript code to specify a type for each parameter. Replacexwithx: numberandywithy: number. You'll notice that the errors are now gone from the parameters, but a new one has appeared under the first argument in the function call: "Argument of type 'string' isn't assignable...
Object.keys(this).forEach( property => { const serialize = Reflect.getMetadata(SerializeMetaKey, this, property); if (serialize) { if (this[property] instanceof Element) { obj[serialize] = this[property].toJSON(); } else { obj[serialize] = this[property]; ...
TypeScript 5.4 adds declarations for JavaScript’s newObject.groupByandMap.groupBystatic methods. Object.groupBytakes an iterable, and a function that decides which "group" each element should be placed in. The function needs to make a "key" for each distinct group, andObject.groupByuses that ...
altKey:boolean; button: number; buttons: number; clientX: number; clientY: number; ctrlKey:boolean;/** * See [DOM Level 3 Events spec](https://www.w3.org/TR/uievents-key/#keys-modifier). for a list of valid (case-sensitive) arguments to this method.*/getModifierState(key: string):...
所以这里的 Record<string, any> 也就是 key 为 string 类型,value 为任意类型的索引类型,可以代替 object 来用,更加语义化一点: 但是不管是返回值类型为 object 还是 Record<string, any> 都存在一个问题:返回的对象不能提示出有哪些属性: 对于习惯了 ts 的提示的同学来说,没有提示太不爽了。怎么能让这个...