---
title: EnumerableExtensions
summary: API reference for EnumerableExtensions.
status: draft
owner: SAIF Doc Gen
last_reviewed: 2026-09-24
library: SAIF.Services
reference_type: package
---

# EnumerableExtensions

Static extension class providing `ChunkBy`, a lazily evaluated helper that splits any `IEnumerable<T>` into successive fixed-size `List<T>` batches, used elsewhere in the codebase to batch work (e.g., bulk operations against external services) into manageable groups*.

## Purpose
- Splits a sequence into fixed-size batches without materializing the whole source sequence up front.

## Context
- Namespace: `SAIF.Services.Utilities`
- Assembly/package: `SAIF.Services` (packaged inside the `SAIF.SAIFCode.Core` NuGet package)

## Public members
| Member | Signature | Purpose |
| --- | --- | --- |
| ChunkBy&lt;T&gt; | `public static IEnumerable<List<T>> ChunkBy<T>(this IEnumerable<T> source, int chunkSize)` | Lazily yields successive `List<T>` chunks of at most `chunkSize` items from `source`, including a final partial chunk if the source length is not an exact multiple of `chunkSize`. |

## Behavioral notes
- Throws `ArgumentException` immediately if `chunkSize` is zero or negative, before any enumeration of `source` begins.
- Uses `yield return`, so chunks are produced incrementally as the caller enumerates the result rather than all at once.

> **Note:** Statements marked with * were inferred from code structure, naming conventions, or
> contextual evidence where direct confirmation was not available in source artifacts. Statements
> marked with ** could not be confirmed; treat as unknown until verified.

## Sources
- Services/SAIF.Services/Utilities/EnumerableExtensions.cs