How to Array.map chain off of async await?

问题

How can I run Array.map off of an await?

const CLASS_PATH = 'User/matt/Github/project';
const PACKAGE_JSON = 'package.json';

const walk = async path => {
  let dirs = [];
  for (const file of await readdir(path)) {
    if ((await stat(join(path, file))).isDirectory()) {
      dirs = [
        ...dirs,
        file,
      ];
    }
  }
  return dirs;
};


async function main() {
  const packagePaths = await walk(CLASS_PATH)
        .map(pkgName => join(CLASS_PATH, pkgName, PACKAGE_JSON));

}
main();

回答1:

Brackets can always be used to change operator predescendence:

 (await walk(CLASS_PATH)).map(/*...*/)

回答2:

You can also use Promise. So in your case:

const packagePaths = await Promise.all(walk(CLASS_PATH).map(async (item): Promise<number> => {
    await join(CLASS_PATH, pkgName, PACKAGE_JSON);
}));

The Promise.all(iterable) method returns a promise that resolves when all of the promises in the iterable argument have resolved, or rejects with the reason of the first passed promise that rejects.

来源：https://stackoverflow.com/questions/56193922/how-to-array-map-chain-off-of-async-await