Unit Testing Error: TypeError: method.startsWith is not a function

[SNEHAASHISH]

const { assert, expect } = require("chai")
const { network, getNamedAccounts, deployments, ethers } = require("hardhat")
const { developmentChains, networkConfig } = require("../../helper-hardhat-config")

!developmentChains.includes(network.name)
    ? describe.skip
    : describe("Raffle Unit Tests", async function () {
          let raffle, vrfCoordinatorV2Mock, raffleEntranceFee, deployer, interval
          const chainId = network.config.chainId

          beforeEach(async function () {
              deployer = (await getNamedAccounts()).deployer
              await deployments.fixture(["all"])
              raffle = await ethers.getContract("Raffle", deployer)
              vrfCoordinatorV2Mock = await ethers.getContract("VRFCoordinatorV2Mock", deployer)
              raffleEntranceFee = await raffle.getEntranceFee()
              interval = await raffle.getInterval()
          })

          describe("constructor", async function () {
              it("initializes the raffle correctly", async function () {
                  const raffleState = await raffle.getRaffleState()
                  const interval = await raffle.getInterval()
                  assert.equal(raffleState.toString(), "0")
                  assert.equal(interval.toString(), networkConfig[chainId]["interval"])
              })
          })

          describe("enterRaffle", async function () {
              it("reverts if you don't pay enough", async function () {
                  await expect(raffle.enterRaffle()).to.be.revertedWith(
                      "Raffle__NotEnoughETHEntered"
                  )
              })
              it("records players when they enter", async function () {
                  await raffle.enterRaffle({ value: raffleEntranceFee })
                  const playerFromContract = await raffle.getPlayer(0)
                  assert.equal(playerFromContract, deployer)
              })
              it("emits event on enter", async function () {
                  await expect(raffle.enterRaffle({ value: raffleEntranceFee })).to.emit(
                      raffle,
                      "RaffleEnter"
                  )
              })
              it("doesn't allow entrance when raffle is calculationg", async function () {
                  await raffle.enterRaffle({ value: raffleEntranceFee })
                  await network.provider.send("evm_increaseTime", [interval.toNumber() + 1])
                  await network.provider.send("evm_mine", [])
                  // Pretending to be a chainlink keeper
                  await raffle.performUpkeep([])
                  await expect(raffle.enterRaffle({ value: raffleEntranceFee })).to.be.revertedWith(
                      "Raffle__NotOpen"
                  )
              })
          })
      })