ti-link-shortener/editor.js

import {EditorState, EditorView, basicSetup} from "@codemirror/basic-setup"
import {markdown} from "@codemirror/lang-markdown"
import {tagExtension} from "@codemirror/state"
import {oneDark, oneDarkHighlightStyle} from "@codemirror/theme-one-dark"

let editableTag = Symbol();

let editor = new EditorView({
    state: EditorState.create({
        extensions: [basicSetup, markdown(), oneDark, oneDarkHighlightStyle, tagExtension(editableTag, EditorView.editable.of(document.getElementById('submit') != null))]
    }),
    parent: document.querySelector("#editor")
});

const setEditorContents = (text) => {
    editor.dispatch({
        changes: {from: 0, to: editor.state.doc.length, insert: text}
    })
};

const syncEditor = (event) => {
    event.preventDefault();
    const successAlert = document.querySelector('#success-alert');
    const errorAlert = document.querySelector('#error-alert');

    fetch('/save', { 
        method: 'POST', 
        headers: { "Content-Type": "application/json; charset=utf-8" }, 
        body: editor.state.sliceDoc()
    })
    .then(res => res.json()) // parse response as JSON (can be res.text() for plain response)
    .then(response => {
        // here you do what you want with response
        console.log(response);

        successAlert.innerHTML = response.msg;
        successAlert.style.display = "block";
        errorAlert.style.display = "none";
    })
    .catch(err => {
        console.log(err);

        errorAlert.innerHTML = err.msg;
        errorAlert.style.display = "block";
        successAlert.style.display = "none";
    });
};

// If we're on the create paste page, set up the submit listener
if (document.getElementById('submit') != null) {
    const submitButton = document.querySelector("#submit");
    submitButton.addEventListener("click", syncEditor);
}

// If we're on the public paste display page, copy the text from the contents div and then delete it
if (document.getElementById('contents') != null) {
    const contentsDiv = document.querySelector("#contents");
    setEditorContents(contentsDiv.textContent);
    contentsDiv.remove();
}