SeleniumHQ/selenium · error · Error

Params must be an instance of ContinueRequestParameters. Rec

Error message

Params must be an instance of ContinueRequestParameters. Received:'${params}'

What it means

Thrown by Network.continueRequest() when params is not an instance of ContinueRequestParameters. The method calls params.asMap() to form the network.continueRequest BiDi command, so it strictly requires that class. A raw object or a different Parameters class fails the instanceof guard before serialization.

Source

Thrown at javascript/selenium-webdriver/bidi/network.js:312

      method: 'network.continueWithAuth',
      params: {
        request: requestId.toString(),
        action: 'cancel',
      },
    }
    await this.bidi.send(command)
  }

  /**
   * Continues the network request with the provided parameters.
   *
   * @param {ContinueRequestParameters} params - The parameters for continuing the request.
   * @throws {Error} If params is not an instance of ContinueRequestParameters.
   * @returns {Promise<void>} A promise that resolves when the command is sent.
   */
  async continueRequest(params) {
    if (!(params instanceof ContinueRequestParameters)) {
      throw new Error(`Params must be an instance of ContinueRequestParameters. Received:'${params}'`)
    }

    const command = {
      method: 'network.continueRequest',
      params: Object.fromEntries(params.asMap()),
    }

    await this.bidi.send(command)
  }

  /**
   * Continues the network response with the given parameters.
   *
   * @param {ContinueResponseParameters} params - The parameters for continuing the response.
   * @throws {Error} If params is not an instance of ContinueResponseParameters.
   * @returns {Promise<void>} A promise that resolves when the command is sent.
   */
  async continueResponse(params) {

View on GitHub (pinned to aa36b38e69)

Solutions

Build a ContinueRequestParameters instance, set the request id and any overrides, then call continueRequest(params): new ContinueRequestParameters(requestId).body(...)...
Always pass the Parameters object, never the bare request id string.
Check that the class you instantiate is ContinueRequestParameters (continueRequest) and not ContinueResponseParameters (continueResponse).

Example fix

// before
await network.continueRequest(event.request.request) // raw object/string

// after
const params = new ContinueRequestParameters(event.request.request)
  .method('GET')
await network.continueRequest(params)

Defensive patterns

Strategy: type-guard

Validate before calling

if (!(params instanceof ContinueRequestParameters)) {
  throw new TypeError('continueRequest requires ContinueRequestParameters')
}

Type guard

function isContinueRequestParameters(v) {
  return v instanceof ContinueRequestParameters
}

Try / catch

try {
  await network.continueRequest(params)
} catch (e) {
  if (/instance of ContinueRequestParameters/.test(e.message)) {
    // wrap the request id in ContinueRequestParameters
  } else throw e
}

Prevention

In intercept handlers, always build ContinueRequestParameters from the event's request id.
Do not pass the raw request object or id string.
Use distinct variable names for request vs response parameters to avoid mix-ups.

When it happens

Trigger: Calling network.continueRequest({...}) with a literal object; passing a request id string directly instead of wrapping it in ContinueRequestParameters; passing a ProvideResponseParameters or ContinueResponseParameters object by mistake.

Common situations: Intercepting a beforeRequestSent event and calling continueRequest with the raw event/request object instead of building the parameters object; reusing a parameter builder from the wrong response method.

Related errors

AI-assisted analysis of SeleniumHQ/selenium@aa36b38e69 (2026-08-14). Data as JSON: /api/errors/976a7c4c785d53f5. Report an issue: GitHub.