Add all candles to client.rest.on

[artdevgame]

Hello,

Thanks for developing this project.

Would it be possible to add the updated Candles[] array to this callback please: https://github.com/bennycode/coinbase-pro-node/blob/main/src/demo/rest-watch-candles.ts#L12

I would like to know the full candle history from when I called client.rest.product.getCandles up until the latest tick.

[bennycode]

Hi @artdevgame, I am happy to hear that you like the project.

The current architecture allows only to get the latest candle. You can subscribe to ProductEvent.NEW_CANDLE events and keep track of all emitted candles in your own application.

Would that be doable for you?

[artdevgame]

Hey @bennycode

I'm using the demo here:
https://github.com/bennycode/coinbase-pro-node/blob/main/src/demo/rest-watch-candles.ts

Here we retrieve all candles and assign to a variable called candles:
https://github.com/bennycode/coinbase-pro-node/blob/main/src/demo/rest-watch-candles.ts#L17

At the moment, the body of the callback (https://github.com/bennycode/coinbase-pro-node/blob/main/src/demo/rest-watch-candles.ts#L13) in my version is pushing candle to the candles array because I need to keep track of the history (I'm looking for trends).

I don't like that my callback is now causing side effects, and would like to solve that somehow, like how array.map has an optional 'array' param: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map

Another way I could solve it is to have the ProductEvent.NEW_CANDLE callback call client.rest.product.getCandles again, but that seems a bit wasteful.

[bennycode]

@artdevgame, I see your use case now. From my point of view, pushing incoming candles to the existing candles array does not sound like a bad idea. The alternative would be to keep all fetched candles in the memory of the "coinbase-pro-node" library, or do you have another approach?

I wouldn't like to store all fetched candles in the memory of "coinbase-pro-node", because it would consume memory even in applications which don't have your use case and it would go beyond the concerns of a REST API.

In your case using an application state container, like Redux, could be a good idea to manage your candles and handle side effects. What do you think?

[artdevgame]

Hey @bennycode, happy new year.

I'm ok pushing to candles for now. I share your concern with the memory allocation so don't think it's something for you to implement in hindsight.

I'll close the ticket. Thanks for the feedback.