DOCUMENTATION

FAST ARRAY is a native Unreal feature that replicates entries in place instead of the entire array.

Built for networked sytems: inventories, equipment slots, abilities, replicated collections, cosmetics changes, save/load lists, and any gameplay system that needs efficient server-authoritative replicated struct data.

Primer FastArray Structs provides a Blueprint-friendly replicated Fast Array container for FInstancedStruct payloads, keyed by stable handles and replicated with Unreal’s per-entry delta serialization.

• Drop the component onto any replicated actor

• define your payload structs as normal

• and replicate flexible gameplay data without building custom FastArray boilerplate every time.

The plugin owns the network envelope; Blueprint owns the data model.

CORE FEATURES

• Per-entry FastArray delta replication for efficient network updates

• Blueprint-friendly FInstancedStruct payload support

• Stable integer handles for referencing entries across systems

• Automatic handle assignment using the lowest available handle

• Authority-only mutation API for server-controlled state

• Add, update, remove, clear, swap, rename, and transfer entries

• Move entries between FastArray components with success/failure outputs

• Blueprint validation gates for add, set, remove, and transfer rules

• Bindable delegates for entry added, changed, and removed events

• Save/load friendly bulk get and set operations

How To

1. Add the Primer Fast Array Structs component to a replicated actor

2. Create your payload structs in Blueprint or C++

3. Build payload values with Make Instanced Struct

4. On the server, call SetEntry, RemoveEntry, or other mutation functions

5. On clients or server, bind to entry delegates and unpack payloads with Get Instanced Struct Value

CONFIGURABLE PARAMETERS

• Payload Structs: Any valid FInstancedStruct payload you author

• Handles: Stable integer keys for each replicated entry

• Validation Gates: Blueprint-overridable rules for adding, setting, removing, or moving entries

• Replication Owner: The replicated actor that owns the component

BLUEPRINT API

• SetEntry - Add or update an entry by handle, or pass -1 to auto-assign a handle

• RemoveEntry - Remove an entry by handle

• ClearEntries - Remove all entries

• SetEntries - Bulk replace entries while preserving handles, useful for save/load

• SwapEntries - Swap payloads between two existing handles

• MoveEntry - Rename an existing handle to a free handle

• MoveEntriesToComponent - Transfer selected entries into another FastArray component

• GetEntry - Retrieve a payload by handle

• GetEntries - Retrieve all entries

• GetFirstAvailableHandle - Preview the next auto-assigned handle

• IsHandleValid - Check whether a handle currently exists

VALIDATION EVENTS

• CanAddEntry - Gate whether a new payload can be added

• CanSetEntry - Gate whether an existing entry can be updated

• CanRemoveEntry - Gate whether an entry can be removed

• CanMoveToTargetComponent - Gate whether an entry can be transferred to another component

DELEGATES

• OnEntryAdded(Handle, Payload) - Fires when an entry is added

• OnEntryChanged(Handle, Payload) - Fires when an entry is updated

• OnEntryRemoved(Handle, Payload) - Fires when an entry is removed

USE CASES

• Replicated inventory and container systems

• Equipment, socket, and loadout state

• Ability, buff, or gameplay effect payload lists

• Server-authoritative item transfer between actors

• Replicated quest, objective, or interaction collections

• Save/load round-tripping for structured gameplay data

PRIMERS

Part of the Primer series, this plugin prioritizes clarity, control, and practical workflows.