JavaScript：使用条件语句解构

Question

I would like to get firstName and lastName properties from a whole user object. I need to use a conditional statement too. How to do something like that?

getUserById(id) and getUserByAddress(id) use the JavaScript find() method that returns an element or undefined .

let { firstName, lastName } = getUserById(id);
if ({ firstName, lastName } === undefined) {
  { firstName, lastName } = getUserByAddress(id);
}
return `${firstName} ${lastName}`;

Answer 1

const { firstName, lastName } = getUserById(id) || getUserByAddress(id) || {};
if (firstName && lastName) {
    return `${firstName} ${lastName}`;
}
return "Unknown user";

If getUserById(id) is falsy, getUserByAddress(id) will be executed. If this is falsy, too, {} will at least prevent throwing an error.

Answer 2

const episodeParser = (
    query: string, codeType ?: string, productId?: number, newProductId?: number
  ) => {
    let queryParams = { 
      query, 
      codeType, 
      processId : AppConfig.PROCESS_ID,
      ...(productId && {productId}),
      ...(newProductId && {newProductId})
    };
    return queryParams;
  }

Here, productId and newProductId both are optional, whatever the value of id will be there, these key will be getting in queryParams.