I've started to read the code and stuff. I'll work on this one as I think it's a good first issue.

Here's what I've made by adding something like this:

fetchAllTaskList (params = {}) {
  const { offset = 0, num = 20, keys } = params
  const activeArgs = compactUndefined([keys])
  const waitingAndStoppedArgs = compactUndefined([offset, num, keys])
  return new Promise((resolve, reject) => {
    this.client.multicall([
      [ 'aria2.tellActive', ...activeArgs ],
      [ 'aria2.tellWaiting', ...waitingAndStoppedArgs ],
      [ 'aria2.tellStopped', ...waitingAndStoppedArgs ]
    ]).then((data) => {
      console.log('fetchAllTaskList data', data)
      const result = mergeTaskResult(data)
      resolve(result)
    }).catch((err) => {
      console.log('fetchAllTaskList fail===>', err)
      reject(err)
    })
  })
}

And here's the result:

But I've got a question here. Are the results here sorted by some date? It doesn't look like that. It's just sorted by the aria2 RPC multicall order and the mergeTaskResult fn just concats the results. Do we have any method or something to sort the results?