> ## Documentation Index
> Fetch the complete documentation index at: https://stackrlabs.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Sequencer

> Ordering is important

Stackr allows applications to perform their own ordering of the actions inside the block
It comes with a basic sequencer which can be extended to perform more complex ordering.

### Strategies

The basic sequencing strategy bundled with the SDK is the FIFO strategy. It does nothing tbh.

```ts theme={null}
import { FIFOStrategy } from "@stackr/stackr-js";

const buildStrategy = new FIFOStrategy();
```

### Custom strategies

You can create your own strategy by extending the `BaseStrategy` and overriding the `orderTxLogic` class and pass it on to the rollup.

Example:

```ts theme={null}
import { BaseStrategy } from "@stackr/stackr-js";

export class Randomize extends BaseStrategy {
  constructor() {
    super("RandomOrder");
  }

  async orderTxLogic(
    actions: Action<AllowedInputTypes>[]
  ): Promise<Action<AllowedInputTypes>[]> {
    console.log("Random");

    return Promise.resolve(
      actions.sort(() => {
        return 0.5 - Math.random();
      })
    );
  }
}
```

Not sure why but you can randomize the order of the actions inside the block like this 🤷🏻‍♂️