Suggestion for Additions to Article on Promise

We can add a section for Promises vs Callbacks to show the inherent advantages of Promise:

Like this :

At the simplest level, Promises are just a different way of working with callbacks. However, there are practical benefits to using them.

1. One real problem with callback based asynchronous programming is that it is common to end up with callbacks
   inside callbacks inside callbacks, with lines of code so highly indented that it is difficult to read.
   Promises allow this kind of nested callback to be re-expressed as a more linear Promise chain that tends to be easier to read and easier to reason about.

2. Another problem with callbacks is that they can make handling errors difficult. If an asynchronous function (or an asynchronously invoked callback) throws an exception, there is no way for that exception to propagate back to the initiator of the asynchronous operation.
   This is a fundamental fact about asynchronous programming: It breaks exception handling.
   The alternative is to meticulously track and propagate errors with callback arguments and return values, but this is tedious and difficult to get right.
   Promises help here by standardizing a way to handle errors and providing a way for errors to propagate correctly through a chain of promises.

Promises are therefore a powerful idiom for asynchronous programming.

issue で参照されている Promises に関する記事を開き、非同期プログラミングについて既に説明されている内容を確認します。ネスト、可読性、エラー伝播に関して提供されたポイントを使って、焦点を絞った「Promises vs Callbacks」セクションを追加し、その後、記事が周囲の内容と一貫していることを確認します。