The environment: `EditorEnvironment`

Some capabilities belong to the page, not to a document: the color scheme, the clipboard, external links, spelling, the UI language and the host's key bindings. Provide them once with configureEditorEnvironment, before the first editor mounts. A later call replaces the whole environment.

Every member is optional. Without the call, the editor is light, English, and has no clipboard, external-link, spelling or host-key behaviour.

Member	What it does	Without it
language	The editor's own UI words: "en", "zh", "ja" or "ko".	English.
colorScheme	{ current(), subscribe(cb) }: the page's "light" / "dark" scheme and its changes.	Always light.
copyText(text)	Put text on the clipboard (the code-block copy button).	No copy button action.
openExternal(url)	A web link was followed (Cmd/Ctrl+click; a plain click in reading mode). Your policy decides how it opens.	Web links do nothing.
refusedLink(url, scheme)	The editor refused a script-capable link (javascript:, data: and similar). Use it to tell the user. Never open the URL.	The refusal is silent.
spell	A SpellService that draws spelling squiggles and offers suggestions.	No spell checking.
handleKey(view, event)	Sees each key before the editor's defaults. Return true to consume it.	The editor's keymap only.

Follow the system color scheme

import { configureEditorEnvironment } from "@openmarkdown-dev/editor";

const media = matchMedia("(prefers-color-scheme: dark)");
configureEditorEnvironment({
  colorScheme: {
    current: () => (media.matches ? "dark" : "light"),
    subscribe: (cb) => {
      const on = () => cb(media.matches ? "dark" : "light");
      media.addEventListener("change", on);
      return () => media.removeEventListener("change", on);
    },
  },
  copyText: (text) => navigator.clipboard.writeText(text),
  openExternal: (url) => window.open(url, "_blank", "noopener"),
});

A mounted editor subscribes while it lives and unsubscribes in destroy. A page with its own theme toggle implements colorScheme over that toggle instead.

Spelling: SpellService

The editor draws its own spelling squiggles and suggestion menu; the checking is yours. A SpellService has six members:

Member	What it does
isOn()	Is spell checking on right now?
onChange(cb)	Follow the on / off state. Returns the unsubscribe.
newDocument()	A fresh spell-document number for one editor, so a checker can keep per-editor ignore lists.
check(doc, paragraphs)	The misspellings (SpellMiss, UTF-16 from / to offsets) for each paragraph, in order, or null when the check could not run.
suggestions(doc, paragraph, from, to)	Up to five suggestions for paragraph.slice(from, to).
closeDocument(doc)	The editor of doc is gone.

Pass checkSpelling: false to createEditorState for an editor that should never show squiggles, such as a small comment box.

Host key bindings

handleKey sees every key the editor's keymap sees, before CodeMirror's defaults. Return true when your binding ran:

import { configureEditorEnvironment } from "@openmarkdown-dev/editor";

configureEditorEnvironment({
  handleKey: (view, event) => {
    if ((event.metaKey || event.ctrlKey) && event.key === "s") {
      save(view.state.doc.toString());
      return true;
    }
    return false;
  },
});

The full signatures are in the API reference.