OasisDEX/oasis-react

import web3 from "../../bootstrap/web3";

function loadContact(abi, contractAddress, noProxy) {
  try {
    if (!web3.isAddress(contractAddress)) {
      throw new Error({
        msg: "contract address argument is not an valid ethereum address"
      });
    }
    const contractFactory = web3.eth.contract(abi);
    if (noProxy) {
      return contractFactory.at(contractAddress);
    }

    const promisify = inner =>
      new Promise((resolve, reject) =>
        inner((err, res) => {
          if (err) {
            reject(err);
          } else {
            resolve(res);
          }
        })
      );

    const proxiedWeb3Handler = {
      get: (target, name) => {
        const inner = target[name];
        if (inner instanceof Function) {
          if (/^[a-z]/.test(name)) {
            return (...args) => {
              return promisify(cb => inner(...args, cb));
            };
          } else {
            return (...args) => {
              const filterInstance = inner(...args);
              target["then"] = filterInstance.watch.bind(filterInstance);
              target["get"] = filterInstance.get.bind(filterInstance);
              return target;
            };
          }
        } else if (typeof inner === "object") {
          return new window.Proxy(inner, proxiedWeb3Handler);
        } else {
          return inner;
        }
      }
    };
    return new window.Proxy(contractFactory.at(contractAddress), proxiedWeb3Handler)
    ;
  } catch (e) {
    console.error(e); // eslint-disable-line no-console
    return null;
  }
}

export default loadContact;