EditContext: compositionend イベント

addEventListener("compositionend", (event) => {});
oncompositionend = (event) => {};

#text-editor {
  border: 1px solid black;
}
#text-editor.is-composing {
  border-color: red;
}

<div id="text-editor"></div>

const editorElement = document.getElementById("text-editor");
const editContext = new EditContext();
editorElement.editContext = editContext;
editContext.addEventListener("compositionstart", (event) => {
  editorElement.classList.add("is-composing");
});
editContext.addEventListener("compositionend", (event) => {
  editorElement.classList.remove("is-composing");
});