### Magicast Development Environment Setup

Source: https://github.com/unjs/magicast/blob/main/README.md

Commands for setting up the Magicast development environment, including enabling Corepack, installing dependencies, and running interactive tests.

```sh
corepack enable
```

```sh
pnpm install
```

```sh
pnpm dev
```

--------------------------------

### Install Magicast Package

Source: https://github.com/unjs/magicast/blob/main/README.md

Instructions for installing the Magicast npm package using popular package managers like Yarn, npm, and pnpm.

```sh
# using yarn
yarn add --dev magicast
```

```sh
# using npm
npm install -D magicast
```

```sh
# using pnpm
pnpm add -D magicast
```

--------------------------------

### Import Magicast Utilities

Source: https://github.com/unjs/magicast/blob/main/README.md

Examples demonstrating how to import core Magicast utilities such as `parseModule`, `generateCode`, `builders`, and `createNode` for both ESM/Bundler and CommonJS environments.

```js
// ESM / Bundler
import { parseModule, generateCode, builders, createNode } from "magicast";
```

```js
// CommonJS
const { parseModule, generateCode, builders, createNode } = require("magicast");
```

--------------------------------

### Robust Error Handling with Magicast

Source: https://github.com/unjs/magicast/blob/main/README.md

Provides an example of wrapping Magicast operations in a `try/catch` block to gracefully handle potential errors during file loading or modification, offering user guidance in case of failure.

```ts
import { loadFile, writeFile } from "magicast";

function updateConfig() {
  try {
    const mod = await loadFile("config.js");

    mod.exports.default.foo.push("b");

    await writeFile(mod);
  } catch {
    console.error("Unable to update config.js");
    console.error(
      "Please update it manually with the following instructions: ..."
    );
    // handle error
  }
}
```

--------------------------------

### Importing Magicast High-Level Helpers

Source: https://github.com/unjs/magicast/blob/main/README.md

Shows how to import specialized helper functions from `magicast/helpers` for common tasks like deep merging objects or adding framework-specific plugins (e.g., Nuxt, Vite).

```js
import {
  deepMergeObject,
  addNuxtModule,
  addVitePlugin,
  // ...
} from "magicast/helpers";
```

--------------------------------

### Manipulating Function Arguments with Magicast

Source: https://github.com/unjs/magicast/blob/main/README.md

Demonstrates how to extract and access arguments from a function call (e.g., `defineConfig`) or a bare object export, allowing programmatic interaction with configuration options passed as arguments.

```js
import { parseModule, generateCode } from "magicast";

const mod = parseModule(`export default defineConfig({ foo: 'bar' })`);

// Support for both bare object export and `defineConfig` wrapper
const options =
  mod.exports.default.$type === "function-call"
    ? mod.exports.default.$args[0]
    : mod.exports.default;

console.log(options.foo); // bar
```

--------------------------------

### Direct AST Manipulation with Magicast

Source: https://github.com/unjs/magicast/blob/main/README.md

Illustrates how to parse a module string into an AST, directly manipulate properties like ensuring an array exists and adding/prepending elements, and then generate the modified code back from the AST.

```js
import { parseModule, generateCode } from "magicast";

// Parse to AST
const mod = parseModule(`export default { }`);

// Ensure foo is an array
mod.exports.default.foo ||= [];
// Add a new array member
mod.exports.default.foo.push("b");
mod.exports.default.foo.unshift("a");

// Generate code
const { code, map } = generateCode(mod);
```

--------------------------------

### Creating Function Calls with Magicast Builders

Source: https://github.com/unjs/magicast/blob/main/README.md

Illustrates how to programmatically create a new function call expression using `builders.functionCall` and assign it to a property within the module's default export, then generate the updated code.

```js
import { parseModule, generateCode, builders } from "magicast";

const mod = parseModule(`export default {}`);

const options = (mod.exports.default.list = builders.functionCall(
  "create",
  [1, 2, 3]
));

console.log(mod.generateCode()); // export default { list: create([1, 2, 3]) }
```

--------------------------------

### Initial config.js File Content

Source: https://github.com/unjs/magicast/blob/main/README.md

The initial content of a `config.js` file, showcasing a default export with a simple object containing an array property.

```js
export default {
  foo: ["a"]
};
```

--------------------------------

### Accessing Raw AST with Magicast

Source: https://github.com/unjs/magicast/blob/main/README.md

Shows how to parse a module and directly access the underlying raw AST object (`$ast`) of a node for advanced manipulation or inspection using external AST tools.

```js
import { parseModule, generateCode } from "magicast";

const mod = parseModule(`export default { }`);

const ast = mod.exports.default.$ast;
// do something with ast
```

--------------------------------

### Modify JavaScript File with Magicast

Source: https://github.com/unjs/magicast/blob/main/README.md

Demonstrates how to load an existing JavaScript file, modify its exported default object by pushing a new element into an array property, and then write the changes back to the file using `loadFile` and `writeFile`.

```js
import { loadFile, writeFile } from "magicast";

const mod = await loadFile("config.js");

mod.exports.default.foo.push("b");

await writeFile(mod, "config.js");
```

--------------------------------

### Generated Code from AST Manipulation

Source: https://github.com/unjs/magicast/blob/main/README.md

The resulting JavaScript code after applying AST manipulations to add and prepend elements to the 'foo' array within the default export.

```js
export default {
  foo: ["a", "b"]
};
```

--------------------------------

### Updated config.js File Content

Source: https://github.com/unjs/magicast/blob/main/README.md

The content of the `config.js` file after being modified by Magicast, showing the 'b' element successfully appended to the 'foo' array.

```js
export default {
  foo: ["a", "b"]
};
```

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