如何在 Typescript 中为 function 就地解构编写类型？

Question

A user will pass an hisObject to myFn . See this simple example:

type HisType = { a:string, b:number };

function myFn( { a, b } = hisObject): void {  
  console.log(a,b)
};

But could can we include that hisObject is of type HisType to avoid errors?

Answer 1

Without default argument:

function myFn({ a, b }: HisType): void {
  console.log(a, b);
}

With default argument ( hisObject points to the default value):

// This exists earlier in the program
const hisObject: HisType = /* ... */;

function myFn({ a, b }: HisType = hisObject): void {
  console.log(a, b);
}