# InstanceStore

> Talos 0.7 · Since 0.6

## Signature

```ts
export interface InstanceStore<T> {
  /** Build and record this entity's instance, replacing any existing one. */
  set(ctx: Keyed, value: T): T
  /** This entity's instance, or null. */
  get(ctx: Keyed): T | null
  /**
   * This entity's instance, building it if the behavior somehow ticked before `init` ran. Named `ensure`
   * rather than `require` so no bundle of a behavior ever contains the bare word the host's sandbox scan
   * looks for.
   */
  ensure(ctx: Keyed, make: () => T): T
  /** Forget this entity's instance. */
  drop(ctx: Keyed): void
  /** How many entities this module is live on; a leak check for tests. */
  readonly size: number
}
```

Import: `import type { InstanceStore } from "@argus/gameplay"`

## Members

| Member | Signature | Description |
|---|---|---|
| `set` | `set(ctx: Keyed, value: T): T` | Build and record this entity's instance, replacing any existing one. |
| `get` | `get(ctx: Keyed): T \| null` | This entity's instance, or null. |
| `ensure` | `ensure(ctx: Keyed, make: () => T): T` | This entity's instance, building it if the behavior somehow ticked before `init` ran. Named `ensure` rather than `require` so no bundle of a behavior ever contains the bare word the host's sandbox scan looks for. |
| `drop` | `drop(ctx: Keyed): void` | Forget this entity's instance. |
| `size` | `readonly size: number` | How many entities this module is live on; a leak check for tests. |