Type Aliases - Making Code Clearer with Generics

When working with generic collections, we often encounter code that’s not immediately clear about its purpose. For example:

// ❌ What does the string means? = new Dictionary<string, string>();

The problem here is that we don’t know what those strings means, what it represents. This problem is called primitive obsession, more can be read here: Primitive Obsession

To solve it we can use aliases:

// Create aliases
using UserId = string;
using ProjectId = string;
// Use the type aliases
// ✅ It's clear that the first string is a UserId and the second string is a ProjectId = new Dictionary<UserId, ProjectId>();

Alternative option is using records:

// Create records
public record UserId(string id);
public record ProjectId(string id);
// Use the type aliases
// ✅ It's clear that the first string is a UserId and the second string is a ProjectId = new Dictionary<UserId, ProjectId>();

Source

For more details about type aliases, check out the original article by Gérald Barré.