Handling Response Data

Requirements Analysis

When we don't set responseType, if the server returns string data, we can try to convert it to a JSON object. For example:

data: "{"a":1,"b":2}"

We convert it to:

data: {
  a: 1,
  b: 2
}

Implementing and Applying the transformResponse Function

Based on the requirements, we need to implement a transformResponse utility function.

helpers/data.ts:

export function transformResponse(data: any): any {
  if (typeof data === 'string') {
    try {
      data = JSON.parse(data)
    } catch (e) {
      // do nothing
    }
  }
  return data
}

index.ts:

function axios(config: AxiosRequestConfig): AxiosPromise {
  processConfig(config)
  return xhr(config).then((res) => {
    return transformResponseData(res)
  })
}

function transformResponseData(res: AxiosResponse): AxiosResponse {
  res.data = transformResponse(res.data)
  return res
}

Looking at the demo again, we can see that the response data field has been parsed from a string to a JSON object structure.

With that, the core features of ts-axios are now implemented. However, up to this point we've only handled the happy path. The next chapter will address various error scenarios.