javascript - 我收到以下错误。未捕获的类型错误：无法读取未定义的属性“文件”

Question

$(document).ready(function() {
      const ipfs = window.IpfsApi({
        host: 'ipfs.infura.io',
        port: 5001,
        protocol: 'https'
      });
      const Buffer = window.IpfsApi().Buffer;
      const ContractAddress = "0xf21ac1844861a76754d7c3db29067cb0970fb8b5";
      if (typeof web3 === "undefined") {
        return showError("Please install MetaMask.");
      }
      const contract = web3.eth.contract(Config.getContractABI()).at(ContractAddress);

      function uploadCertificate() {
        //TODO: Write the Logic behind Uploading a Certificate to IPFS and adding the information to the Blockchain
        let filesDiv = $("#certificateForUpload");
        if (filesDiv[0].files.length === 0) {
          return showError("Please select a file.");
        }

        let fileReader = new FileReader();
        fileReader.onload = function() {
          let fileBuffer = Buffer.from(fileReader.result);
          ipfs.files.add(fileBuffer, (err, result) => {
            if (err) {
              return showError(err);
            }

            if (result) {
              let ipfsHash = result[0].hash;
              contract.addCertificate(ipfsHash, function(err, result) {
                if (err) {
                  return showError("There was error with smart contract: $(err)")
                }
                showInfo("Certificate $(ipfsHash) was <b> successfully added.</b> to the Registry.")
              })
            }

          });
        };
        fileReader.readAsArrayBuffer(filesDiv[0].files[0]);

      }

标签： javascriptnode.jsajaxethereumipfs