“未知"与“任何"

问题描述

TypeScript 3.0根据其Wiki引入了unknown类型:

TypeScript 3.0 introduces unknown type, according to their wiki:

unknown和any有什么区别?什么时候应该在any上使用unknown?

What is difference between unknown and any? When should we use unknown over any?

推荐答案

您可以在 PR 或 RC公告，但要旨是:

You can read more about unknown in the PR or the RC announcement, but the gist of it is:

一些例子:

let vAny: any = 10;          // We can assign anthing to any
let vUnknown: unknown =  10; // We can assign anthing to unknown just like any 


let s1: string = vAny;     // Any is assigable to anything 
let s2: string = vUnknown; // Invalid we can't assign vUnknown to any other type (without an explicit assertion)

vAny.method();     // ok anything goes with any
vUnknown.method(); // not ok, we don't know anything about this variable

建议的用法是:

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