流动型。 {} 和 {||} 类型有什么区别

Question

I dont know what is the exact differences.我不知道确切的区别是什么。

I want to know what is the differences我想知道有什么区别

Answer 1

According to doc https://flow.org/en/docs/types/objects/#toc-exact-object-types {||} is a way to check for “exact” object types => no extra properties will be authorized with type with {||} syntax根据文档https://flow.org/en/docs/types/objects/#toc-exact-object-types {||}是一种检查“精确” object 类型的方法 => 不会授权额外的属性带有{||}语法的类型

sample from doc文件样本

// @flow
var foo: {| foo: string |} = { foo: "Hello", bar: "World!" }; // Error!

=> failed because foo can only have a foo property. => 失败，因为 foo 只能有一个 foo 属性。 Bar is unauthorized酒吧未经授权

but if you do the following it will work但如果您执行以下操作，它将起作用

var foo: { foo: string } = { foo: "Hello", bar: "World!" }; // Work