How can I close a Web Serial port

Question

I want to close the serial port after a condition is met.

if (result !== null && i == 1) { 
            Swal.fire("error!", "", "error"); 
            port. close();
            break;
          } 

if (result2 !== null && i == 1) {
            Swal.fire("success!", "", "success");
            port. close();
            break;
          }

use port.close(); But the problem encountered is that the serial port cannot be close. and a warning message saying "Uncaught (in promise) TypeError: Failed to execute 'close' on 'SerialPort': Cannot cancel a locked stream at connectSerial" How should I fix it? Thanks.

async function connectSerial() {
    const log = document.getElementById("target");
    try {
      const ports = await navigator.serial.getPorts();
      const port = ports[0];
      const bufferSize = 1024;
      await port.open({ baudRate: 115200, bufferSize });
      const decoder = new TextDecoderStream();
      const inputStream = decoder.readable;
      const reader = inputStream.getReader();
      port.readable.pipeTo(decoder.writable);

      let Number = $("#Number").val();
      $.ajax({
        url: "example.php",
        method: "POST",
        data: {
          Number: Number,
        },
        dataType: "json",
      })
        .done(async function (data) {
          let asciiVal = data.hex;
          const encoder = new TextEncoder();
          const writer = port.writable.getWriter();
          await writer.write(encoder.encode(asciiVal));
        })
        .fail(function (jqXHR, textStatus, errorThrown) {
          console.log("Ajax request failed: " + textStatus);
        });

      let i = 0;
      while (true) {
        const { value, done } = await reader.read();
        if (value) {
          log.textContent += value + "\n";
          let text = value;
          let result = text.match("CN");
          let result2 = text.match("APPROVAL");
          if (result !== null && i == 1) {
            Swal.fire("error!", "", "error");
            port.close();
            break;
          }

          if (result2 !== null && i == 1) {
            Swal.fire("success!", "", "success");
            port.close();
            break;
          }
        }

        if (done) {
          console.log("[readLoop] DONE", done);
          reader.releaseLock();
          break;
        }
        i++;
      }
    } catch (error) {
      log.innerHTML = error;
    }
  }