isComposing in onInput is always `true` while you turn on IME until recomposition only in Chromium

[tats-u]

https://codepen.io/tats-u/pen/VYZBEWM (simple Markdown-to-HTML playground)

The following process doesn't work in Chromium. Works in Firefox as intended. Which behavior is correct?

document.addEventListener("DOMContentLoaded", () => {
  const textArea = document.querySelector("textarea");
  textArea.addEventListener("input", (event) => {
    if (event.isComposing) { // skip while IME input because it's half-baked
    return;
  }
    // your process here
  });
});

Reproduction:

1. Open https://codepen.io/tats-u/pen/VYZBEWM in a Chromium-based browser
2. Turn your IME on (e.g. Google Japanese Input / Microsoft Japanese Input)
3. Input some Japanese using IME
4. Press Enter to commit

• Firefox: the rendered HTML will be changed
• Chromium: HTML is will not be changed

[tats-u]

Firefox is correct → we have to send a bug report to https://bugs.chromium.org/
Chromium is correct → we have to revise the specifications first

[tats-u]

According to #202, the behavior of Chromium is "correct". It sucks and must be revised.