WebViewBridge.js

/* Usage examples:
import DeviceInfo from "react-native-device-info";

WebViewBridge.addSyncFunction("getDeviceId", DeviceInfo.getUniqueID);

const customAsyncFunction = (arg1, arg2, callback) => {
  callback(null, "success");
});

WebViewBridge.addAsyncFunction("myFunctionName", asyncFunction);
*/
export default {
  // Prepare an empty functions object
  functions: {},

  // Accepts a name and a function which accepts two arguments:
  // an array of args and callback with signature (err, res)
  addFunction(name, normalizedFunc) {
    if (this.functions[name]) {
      console.warn(`Overwriting WebViewBridge function ${name}!`);
    }

    this.functions[name] = normalizedFunc;
  },

  // Accepts an asynchronous function which accepts any number of
  // arguments, followed by a callback with signature (err, res)
  addAsyncFunction(name, func) {
    this.addFunction(name, function(args, callback) {
      func(...args, callback);
    });
  },

  // Accepts a synchronous function which accepts any number of
  // arguments and returns any value
  addSyncFunction(name, func) {
    this.addFunction(name, function(args, callback) {
      try {
        callback(null, func(...args));
      } catch (err) {
        callback(err);
      }
    });
  }
};