What is the purpose of Promise.resolve(x).then(x => y)

[JackieKu]

There are many instances in ethers.js that create immediately resolved promise and await on it. For example,

• https://github.com/ethers-io/ethers.js/blob/master/packages/providers/src.ts/base-provider.ts#L1212
• https://github.com/ethers-io/ethers.js/blob/master/packages/providers/src.ts/base-provider.ts#L1233

const hexTx = await Promise.resolve(signedTransaction).then(t => hexlify(t));
tx[key] = Promise.resolve(values[key]).then((v) => (v ? this._getAddress(v): null));

Why not

const hexTx = hexlify(signedTransaction);
tx[key] = Promise.resolve(values[key] ? this._getAddress(values[key]): null);

Because this pattern is used intensively, I suppose they were done on purpose. But I could not find a something clear.

[ricmoo]

Most methods (especially in the provider, where things are already wildly async) take in either a Promise<string> | string. By passing it through Promise.resolve, the logic is greatly simplified. This may be changing in v6, still contemplating about it, since await is now fairly widespread. :)

But for example, in your above example for the second case, hexlify(signedTransaction) would result in an error if a Promise<string> was passed in for signedTransaction.

Make sense?