patchJavaScriptRuntime function

Future patchJavaScriptRuntime(FlutterQjs engine)

Extend the JavaScript runtime with some missing stuff so that it can work together with RxDB JavaScript code.

Implementation

Future<dynamic> patchJavaScriptRuntime(FlutterQjs engine) async {
  final prefs = await SharedPreferences.getInstance();

  await engine.evaluate('process = {};');
  await engine.evaluate('window = {};');
  await engine.evaluate('console = {};');

  await engine.evaluate('BigInt = {};');
  await engine.evaluate('BigInt64Array = {};');
  await engine.evaluate('BigUint64Array = {};');


  final setToGlobalObject =
      await engine.evaluate("(key, val) => { this[key] = val; }");
  await setToGlobalObject.invoke([
    "setTimeoutWait",
    (int time) async {
      await Future.delayed(Duration(milliseconds: time));
    }
  ]);
  await engine.evaluate("""
          let timeoutId = 0;
          let runningTimeouts = new Set();
          function setTimeout(fn, time) {
            let id = timeoutId++;
            runningTimeouts.add(id);
            (async() => {
              await setTimeoutWait(time);
              if(!runningTimeouts.has(id)){
                return;
              }
              clearTimeout(id);
              fn();
            })();
            return id;
          }
          function clearTimeout(id) {
            runningTimeouts.delete(id);
          }
        """);
  await engine.evaluate("""
          let intervalid = 0;
          let intervalMap = {};
          function setInterval(callback, delay = 0, ...args) {
            let id = intervalid++;
            function repeat() {
              intervalMap[id] = setTimeout(() => {
              callback(...args)
              if(intervalMap[id]) {
                repeat()
              }
            }, delay)
            }
            repeat();
            return id;
          }
          function clearInterval(intervalid) {
            clearTimeout(intervalMap[intervalid])
            delete intervalMap[intervalid]
          }
  """);
  await setToGlobalObject.invoke([
    "persistKeyValue",
    (String key, String value) async {
      await prefs.setString(key, value);
    }
  ]);
  await setToGlobalObject.invoke([
    "readKeyValue",
    (String key) async {
      final String? value = prefs.getString(key);
      return value;
    }
  ]);

  return setToGlobalObject;
}