Oaphi

var PropertyLock = (() => {

    let locked = false;
    let timeout = 0;

    const store = PropertiesService.getScriptProperties();

    const propertyName = "locked";
    const triggerName = "PropertyLock.releaseLock";

Oaphi

Preliminary

1. Does the Web App have a saved deployment? ("Publish" -> "Deploy as Web App")
2. Are you accessing the /dev endpoint (https://script.google.com/.../yourIdHere/dev)?
3. If you are accessing the /exec endpoint (https://script.google.com/.../yourIdHere/exec), did you redeploy?
4. If you redeployed, did you increment the script version?
5. If you have a client-side problem, what does the console say (pres F12 to open developer tools)?
6. If you have a server-side problem, what do executions say (https://script.google.com/home/projects/yourIdHere/executions

Web App Access

Oaphi

/**
 * Promise-friendly google.script.run call
 * @param {String} funcName
 * @param {...*} params
 * @returns {Promise}
 */
const asyncGAPI = (funcName, ...params) => {
    return new Promise((res, rej) => {
        google.script.run
            .withSuccessHandler(data => res(data))