Make google.script.run looks a promise

google-script-run-promise.js

// Converted https://gist.github.com/shrugs/44cfb94faa7f09bcd9cb for ES6

function scriptRunPromise() {
  const gs = {};
  
  // google.script.run contains doSomething() methods at runtime.
  // Object.keys(goog.sscript.run) returns array of method names.
  const keys = Object.keys(google.script.run);
  
  // for each key, i.e. method name...
  for (let i=0; i < keys.length; i++) {
    // assign the function to gs.doSomething() which returns...
    gs[keys[i]] = (function(key) {
      // a function which accepts arbitrary args and returns...
      return function(...args) {
        // a promise that executes ...
        return new Promise(function(resolve, reject) {
          google.script.run
            .withSuccessHandler(resolve)
            .withFailureHandler(reject)[key]
            .apply(google.script.run, args);
        });
      };
    })(keys[i]);
  }
  return gs;
  // gs.doSomething() returns a promise that will execulte 
  // google.script.run.withSuccessHandler(...).withFailureHandler(...).doSomething()
}

// usage with .then()
scriptRunPromise().doSomething().then((result) => {/* process result */}, (err)=>{/* handle err */});

// usage with async/await
async function foo() {
  try {
    const result = await scriptRunPromise().doSomething();
    // process result
  } catch(error) {
    // handle error
  }
}

Perfect, just what I was looking for!

How can I pass user object? I am meaning withUserObject(). Just pass it along?