# ContextVariableMap

**Kind:** Interface

**Source:** [`src/context.ts`](https://github.com/honojs/hono/blob/main/src/context.ts#L57)

Interface for context variable mapping.

`ContextVariableMap` defines the named values stored in a context. Context writers add or update entries in the map, while context consumers read entries by variable name.

## Diagram

```mermaid
graph LR
  Writer[Context Writer] --> Map[ContextVariableMap]
  Map --> Reader[Context Consumer]
```

## Usage

```ts
function readContextValue(
  variables: ContextVariableMap,
  name: string,
) {
  return variables[name];
}

const variables: ContextVariableMap = {
  locale: "en-US",
  userName: "Alex",
};

const locale = readContextValue(variables, "locale");
```

## AI Coding Instructions

- Type dynamically keyed context values as `ContextVariableMap`.
- Keep variable names consistent between context writers and consumers.
- Handle missing values when reading entries from the map.
- Update context creation and lookup code together when adding a new variable name.