我从官方复制/粘贴答案github的VS代码： https://github.com/Microsoft/vscode/issues/ 28495＃event-1119847030 。

I copy/paste the answer from the official github's VS Code : https://github.com/Microsoft/vscode/issues/28495#event-1119847030.

为我们的JS和TS语言提供支持的TypeScript服务目前无法识别属性在创建对象后添加到对象中。

The TypeScript service that powers our JS and TS language currently cannot recognize properties added to an object after it is created.

***解决方法是定义对象文字中的所有属性：

The best workaround is to define all the properties in the object literal:

var person = {
   name: "azeaze",
   sayHello: function() {
     console.log("Hi! My name is ", this.name)
  }
}

或添加一个明确的使用jsdocs输入：

or to add an explicit type using jsdocs:

/**
 * @type {{ name: string, sayHello: () => void}}
 */
// @ts-ignore
var person = {}

person.name = "azeaze"

person.sayHello = function() {
  console.log("Hi! My name is ", this.name)
}