Data Service

Introduction

Slot Engine has data layers that store JSON data required for game optimization, statistical analysis and frontend visualization.

Book

Each simulation produces a "book" that contains information about the simulation, like simulation ID, payout values, and JSON data for frontend visualization.

The book stores events as an array of objects with an index, type and arbitrary data. Events define, in chronological order, what should be displayed to the player on the frontend.

Common events include:

Revealing the board symbols
Displaying win lines
Displaying win amount
Trigger free spins screen

In short: (Almost) every visual change on the frontend for a single spin is defined inside a book.

For example:

ctx.services.data.addBookEvent({
  type: "show-winlines",
  data: {
    lines: [0, 3]
    wins: [
      [
        { reel: 0, row: 0 },
        { reel: 1, row: 0 },
        { reel: 2, row: 0 },
      ],
      [
        { reel: 0, row: 2 },
        { reel: 1, row: 2 },
        { reel: 2, row: 2 },
      ],
    ]
  }
})

ctx.services.data.addBookEvent({
  type: "add-update-balance",
  data: {
    value: 200,
  }
})

Each added event receives an auto-incremented index, allowing the frontend to process events in the correct chronological order.

Tagging allows grouping simulations by arbitrary criteria. If using optimization, this would allow you to target specific simulations to optimize. It also enables capturing notable runs (e.g. max win simulations) so they can be replayed locally for debugging or demonstration.

Tags are written to the __build__ directory as tags_<gameMode>.json. The JSON structure matches the Stake Math SDK format for interoperability.

Without having to configure anything, Slot Engine automatically tags simulations with their result set criteria. You can add additional tags as needed using tag().

Tags are also used to enable filtering books when browsing them with Panel.

Methods

log()

Method	Type
`ctx.services.data.log()`	`(message: string) => void`

Write a log to the terminal UI. This is more reliable than console.log.

addBookEvent()

Method	Type
`ctx.services.data.addBookEvent()`	`(event) => void`

Parameters

Parameter	Type
`event`	`{ type: string, data: Record<string, any> }`

Adds a new event to the current book.

tag()

Method	Type
`ctx.services.data.tag()`	`(data) => void`

Parameters

Parameter	Type
`data`	`Record<string, string \| number \| boolean>`

Tag the current simulation for statistical analysis and book filtering.

tagSymbolOccurrence()

Method	Type
`ctx.services.data.tagSymbolOccurrence()`	`(data) => void`

Parameters

Parameter	Type
`data`	`{ kind: number; symbolId: string; [key: string]: any; }`

A wrapper around ctx.services.data.tag() to tag symbol occurrences. Win types already call this under the hood to document symbol hits.

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