### Install Craft library via package manager

Source: https://github.com/sylphxltd/craft/blob/main/README.md

Demonstrates installing @sylphx/craft using various package managers. Run the appropriate command in your terminal to add the library to your project.

```Bash
# Using bun (recommended)
bun add @sylphx/craft

# Using npm
npm install @sylphx/craft
# Using pnpm
pnpm add @sylphx/craft

# Using yarn
yarn add @sylphx/craft
```

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

### Quick start: immutable update with craft

Source: https://github.com/sylphxltd/craft/blob/main/README.md

Shows a basic example of using craft to produce a new immutable state from a base object while mutating a draft inside the producer function.

```TypeScript
import { craft } from "@sylphx/craft";

const baseState = {
  user: { name: "Alice", age: 25 },
  todos: [
    { id: 1, text: "Learn Craft", done: false },
    { id: 2, text: "Use Craft", done: false },
  ],
};

const nextState = craft(baseState, (draft) => {
  draft.user.age = 26;
  draft.todos[0].done = true;
  draft.todos.push({ id: 3, text: "Master Craft", done: false });
});

// Original is unchanged
console.log(baseState.user.age); // 25

// New state has the updates
console.log(nextState.user.age); // 26
console.log(nextState.todos.length); // 3

// Structural sharing - unchanged parts are the same reference
console.log(baseState.todos[1] === nextState.todos[1]); // true
```

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

### Craft Development Commands with Bun

Source: https://github.com/sylphxltd/craft/blob/main/README.md

Set of commands for managing the Craft project lifecycle, including installation, testing, linting, formatting, type checking, and building. Depends on Bun package manager; inputs are project files, outputs are reports or built artifacts. Run individually as needed.

```bash
# Install dependencies
bun install

# Run tests
bun test

# Run tests in watch mode
bun test:watch

# Run benchmarks
bun bench

# Type checking
bun run typecheck

# Linting
bun run lint

# Format code
bun run format

# Build
bun run build
```

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

### Immutable State Updates: Manual vs Craft

Source: https://github.com/sylphxltd/craft/blob/main/README.md

This example contrasts verbose manual immutable updates using spread operators with Craft's concise draft-based API for nested state changes. It requires a state object as input and produces an immutable nextState. Limitations include needing the Craft library imported; works with any mutable state structure.

```typescript
// ❌ Manual (error-prone, verbose, slow)
const nextState = {
  ...state,
  user: {
    ...state.user,
    profile: {
      ...state.user.profile,
      age: state.user.profile.age + 1,
    },
  },
};

// ✅ Craft (simple, safe, fast)
const nextState = craft(state, (draft) => {
  draft.user.profile.age++;
});
```

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

### Get Immutable Snapshot with current (TypeScript)

Source: https://context7.com/sylphxltd/craft/llms.txt

The current function gets an immutable snapshot of the current draft state. Imported from @sylphx/craft, used within a producer to capture intermediates. Outputs a frozen object, ensuring immutability for safe sharing, but limited to use inside producers.

```typescript
import { craft, current } from "@sylphx/craft";

interface State {
  items: number[];
  metadata: { lastUpdate: number };
}

let snapshot: State;

const state: State = {
  items: [1, 2, 3],
  metadata: { lastUpdate: 0 }
};

const next = craft(state, (draft) => {
  draft.items.push(4);
  draft.items.push(5);
  draft.metadata.lastUpdate = Date.now();

  // Get frozen snapshot for use outside producer
  snapshot = current(draft);
});

// Snapshot is immutable and safe to share
console.log(snapshot.items); // [1, 2, 3, 4, 5]
console.log(Object.isFrozen(snapshot)); // true
```

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

### Get Immutable Snapshot of Draft State (TypeScript)

Source: https://github.com/sylphxltd/craft/blob/main/README.md

Provides an immutable snapshot of the current draft state within a producer function. This is useful for capturing the state at a specific point in time before further mutations occur. It relies on the `current` function from the Craft library.

```typescript
let snapshot;

craft(state, (draft) => {
  draft.items.push(4);
  snapshot = current(draft); // Frozen snapshot
});

// Use snapshot outside producer
console.log(snapshot.items); // [1, 2, 3, 4]
```

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

### Running Craft Benchmarks with Bun

Source: https://github.com/sylphxltd/craft/blob/main/README.md

Executes performance benchmarks to compare Craft against Immer across array, Map/Set, and JSON patch operations. Requires Bun runtime and project dependencies; outputs timing results to console. Best for local verification of speed claims.

```bash
bun bench
```

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

### Fluent API with composer

Source: https://github.com/sylphxltd/craft/blob/main/README.md

Demonstrates the `composer` fluent interface for chaining multiple draft mutations before producing a new state.

```TypeScript
const updater = composer<State>((draft) => {
  draft.count++;
})
  .with((draft) => {
    draft.name = "Bob";
  })
  .with((draft) => {
    draft.active = true;
  });

const nextState = updater.produce(baseState);
```

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

### Sequential producers with pipe

Source: https://github.com/sylphxltd/craft/blob/main/README.md

Applies a series of producer functions in order using the `pipe` utility, returning the final immutable state.

```TypeScript
const result = pipe(
  baseState,
  (draft) => {
    draft.count++;
  },
  (draft) => {
    draft.count *= 2;
  },
  (draft) => {
    draft.name = "Result";
 },
);
```

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

### Fluent API for chaining producers with composer

Source: https://context7.com/sylphxltd/craft/llms.txt

The composer function provides a fluent API for chaining multiple producers together. It allows building complex state transformations through method chaining with the .with() method, making the composition more readable and maintainable.

```typescript
import { composer } from "@sylphx/craft";

interface TodoState {
  todos: Array<{ id: number; text: string; done: boolean }>;
  filter: string;
  count: number;
}

const updater = composer<TodoState>((draft) => {
  draft.count++;
})
  .with((draft) => {
    draft.filter = "active";
  })
  .with((draft) => {
    draft.todos.push({ id: 3, text: "New todo", done: false });
  });

const state: TodoState = {
  todos: [
    { id: 1, text: "Learn", done: false },
    { id: 2, text: "Practice", done: true }
  ],
  filter: "all",
  count: 0
};

const nextState = updater.produce(state);

console.log(nextState.count); // 1
console.log(nextState.filter); // "active"
console.log(nextState.todos.length); // 3
```

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

### Map and Set Mutations (TypeScript)

Source: https://github.com/sylphxltd/craft/blob/main/README.md

Demonstrates Craft's support for ES6 Map and Set collections, enabling automatic mutation tracking for these data structures. It shows how to perform operations like adding, deleting, and updating elements within Maps and Sets.

```typescript
import { craft } from "@sylphx/craft";

// Map mutations
const state = {
  users: new Map([
    ["alice", { name: "Alice", age: 25 }],
    ["bob", { name: "Bob", age: 30 }],
  ]),
};

const next = craft(state, (draft) => {
  draft.users.set("charlie", { name: "Charlie", age: 35 });
  draft.users.delete("alice");
  const bob = draft.users.get("bob");
  if (bob) bob.age = 31;
});

// Set mutations
const state = {
  tags: new Set(["javascript", "typescript"]),
};

const next = craft(state, (draft) => {
  draft.tags.add("react");
  draft.tags.delete("javascript");
});
```

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

### Combine producers using compose

Source: https://github.com/sylphxltd/craft/blob/main/README.md

Uses the `compose` utility to merge multiple producer functions into a single one that can be passed to `craft`.

```TypeScript
const increment = (draft: State) => {
  draft.count++;
};
const activate = (draft: State) => {
  draft.active = true;
};

const nextState = craft(baseState, compose(increment, activate));
```

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

### Generate and Apply JSON Patches (TypeScript)

Source: https://github.com/sylphxltd/craft/blob/main/README.md

Illustrates how to generate JSON patches (RFC 6902) to track state mutations, enabling features like undo/redo and time-travel debugging. It shows the use of `craftWithPatches` to produce patches and `applyPatches` to revert or recreate states.

```typescript
import { craftWithPatches, applyPatches } from "@sylphx/craft";

const [nextState, patches, inversePatches] = craftWithPatches(state, (draft) => {
  draft.count = 5;
  draft.user.name = "Bob";
  draft.items.push({ id: 3 });
});

// patches describe the changes:
// [
//   { op: 'replace', path: ['count'], value: 5 },
//   { op: 'replace', path: ['user', 'name'], value: 'Bob' },
//   { op: 'add', path: ['items', 2], value: { id: 3 } }
// ]

// Apply patches to recreate state
const recreated = applyPatches(state, patches);
console.log(recreated === nextState); // true (deep equal)

// Undo changes using inverse patches
const reverted = applyPatches(nextState, inversePatches);
console.log(reverted === state); // true (deep equal)
```

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

### Pipe State with Producers (TypeScript)

Source: https://context7.com/sylphxltd/craft/llms.txt

The pipe function applies multiple producer functions sequentially to a base state, enabling chained state mutations. It requires the @sylphx/craft library and takes an initial state plus an array of producer functions as inputs. Outputs the final mutated state, with limitations in handling asynchronous operations.

```typescript
import { pipe } from "@sylphx/craft";

interface CounterState {
  count: number;
  history: number[];
}

const state: CounterState = {
  count: 5,
  history: []
};

const result = pipe(
  state,
  (draft) => {
    draft.history.push(draft.count);
    draft.count++;
  },
  (draft) => {
    draft.history.push(draft.count);
    draft.count *= 2;
  },
  (draft) => {
    draft.history.push(draft.count);
    draft.count += 10;
  }
);

console.log(result);
// { count: 22, history: [5, 6, 12] }
```

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

### Manual draft control with createDraft and finishDraft

Source: https://github.com/sylphxltd/craft/blob/main/README.md

Illustrates advanced usage where a draft is created manually, mutated over time (e.g., async), and then finalized into an immutable state.

```TypeScript
const draft = createDraft(state);

// Make changes over
await fetchData().then(data => {
  draft.user = data;
});

draft.count++;

// Finalize when ready
const nextState = finishDraft(draft);
```

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

### Apply Patches with applyPatches in TypeScript

Source: https://context7.com/sylphxltd/craft/llms.txt

applyPatches mutates a base state using a series of JSON Patch operations, useful for syncing or replaying history. It requires @sylphx/craft import and Patch type; inputs are base state and patches array; outputs a new patched state; supports undo/redo via inverse patches but may fail on invalid paths.

```typescript
import { applyPatches, type Patch } from "@sylphx/craft";

interface AppState {
  todos: Array<{ id: number; text: string; done: boolean }>;
  filter: string;
}

const state: AppState = {
  todos: [
    { id: 1, text: "Learn", done: false },
    { id: 2, text: "Practice", done: false }
  ],
  filter: "all"
};

// Patches from server or history
const patches: Patch[] = [
  { op: "replace", path: ["todos", 0, "done"], value: true },
  { op: "replace", path: ["filter"], value: "active" },
  { op: "add", path: ["todos", 2], value: { id: 3, text: "Master", done: false } }
];

const nextState = applyPatches(state, patches);

console.log(nextState.todos[0].done); // true
console.log(nextState.filter); // "active"
console.log(nextState.todos.length); // 3

// Use case: Undo/Redo system
const history: Patch[][] = [];
const inverseHistory: Patch[][] = [];

function makeChange(current: AppState, changeProducer: any): AppState {
  const [next, patches, inverse] = craftWithPatches(current, changeProducer);
  history.push(patches);
  inverseHistory.push(inverse);
  return next;
}

function undo(current: AppState): AppState {
  const inverse = inverseHistory.pop();
  return inverse ? applyPatches(current, inverse) : current;
}

function redo(current: AppState): AppState {
  const patches = history[inverseHistory.length];
  return patches ? applyPatches(current, patches) : current;
}
```

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

### Core function craft usage

Source: https://github.com/sylphxltd/craft/blob/main/README.md

Demonstrates the primary `craft` function to mutate a draft and automatically return a new immutable state. The producer can freely modify the draft.

```TypeScript
const nextState = craft(currentState, (draft) => {
  // Mutate draft as you like
  draft.count++;
  draft.user.name = "Bob";
});
```

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

### Handle Set Operations (TypeScript)

Source: https://context7.com/sylphxltd/craft/llms.txt

Craft supports ES6 Set mutations with automatic tracking. Imports needed from @sylphx/craft, manipulates Set objects in state. Allows adding/deleting elements, outputting the updated Set state.

```typescript
import { craft } from "@sylphx/craft";

interface State {
  tags: Set<string>;
  activeIds: Set<number>;
}

const state: State = {
  tags: new Set(["javascript", "typescript"]),
  activeIds: new Set([1, 2, 3])
};

const next = craft(state, (draft) => {
  // Add elements
  draft.tags.add("react");
  draft.tags.add("node");

  // Delete elements
  draft.tags.delete("javascript");

  // Modify numeric set
  draft.activeIds.add(4);
  draft.activeIds.delete(1);
});

console.log(Array.from(next.tags));
// ["typescript", "react", "node"]

console.log(Array.from(next.activeIds));
// [2, 3, 4]

console.log(next.tags.has("javascript")); // false
console.log(next.activeIds.has(4)); // true
```

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

### Handle Map Operations (TypeScript)

Source: https://context7.com/sylphxltd/craft/llms.txt

Craft provides full support for ES6 Map mutations with automatic tracking. Imports from @sylphx/craft, operates on Map objects in state. Supports add, delete, modify, and update operations, outputting the mutated state.

```typescript
import { craft } from "@sylphx/craft";

interface State {
  users: Map<string, { name: string; age: number }>;
  metadata: Map<string, any>;
}

const state: State = {
  users: new Map([
    ["alice", { name: "Alice", age: 25 }],
    ["bob", { name: "Bob", age: 30 }]
  ]),
  metadata: new Map([["version", 1]])
};

const next = craft(state, (draft) => {
  // Add new entry
  draft.users.set("charlie", { name: "Charlie", age: 35 });

  // Delete entry
  draft.users.delete("alice");

  // Modify nested value
  const bob = draft.users.get("bob");
  if (bob) {
    bob.age = 31;
  }

  // Update metadata
  draft.metadata.set("version", 2);
  draft.metadata.set("lastUpdate", Date.now());
});

console.log(next.users.size); // 2
console.log(next.users.get("bob")?.age); // 31
console.log(next.users.has("alice")); // false
console.log(next.metadata.get("version")); // 2
```

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

### Compose multiple producers with compose utility

Source: https://context7.com/sylphxltd/craft/llms.txt

The compose function combines multiple producer functions into a single producer that applies all changes in sequence. This enables functional composition patterns and allows building complex state transformations from simple, reusable producer functions.

```typescript
import { craft, compose } from "@sylphx/craft";

interface State {
  count: number;
  name: string;
  active: boolean;
}

const increment = (draft: State) => {
  draft.count++;
};

const activate = (draft: State) => {
  draft.active = true;
};

const rename = (draft: State) => {
  draft.name = "Bob";
};

const baseState = { count: 0, name: "Alice", active: false };

// Apply all producers at once
const nextState = craft(baseState, compose(increment, activate, rename));

console.log(nextState);
// { count: 1, name: "Bob", active: true }
```

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

### Generate Patches with craftWithPatches in TypeScript

Source: https://context7.com/sylphxltd/craft/llms.txt

craftWithPatches produces a new state, forward patches, and inverse patches from a draft mutation, enabling undo/redo and sync features. It depends on the @sylphx/craft import and works with any mutable draft object. Inputs are base state and a producer function; outputs are next state, patches array, and inverse patches array; limitations include potential performance overhead for deep objects.

```typescript
import { craftWithPatches, applyPatches } from "@sylphx/craft";

interface State {
  count: number;
  user: { name: string };
  items: Array<{ id: number }>;
}

const state: State = {
  count: 0,
  user: { name: "Alice" },
  items: [{ id: 1 }, { id: 2 }]
};

// Generate state and patches
const [nextState, patches, inversePatches] = craftWithPatches(state, (draft) => {
  draft.count = 5;
  draft.user.name = "Bob";
  draft.items.push({ id: 3 });
});

console.log(patches);
// [
//   { op: 'replace', path: ['count'], value: 5 },
//   { op: 'replace', path: ['user', 'name'], value: 'Bob' },
//   { op: 'add', path: ['items', 2], value: { id: 3 } }
// ]

console.log(inversePatches);
// [
//   { op: 'replace', path: ['count'], value: 0 },
//   { op: 'replace', path: ['user', 'name'], value: 'Alice' },
//   { op: 'remove', path: ['items', 2] }
// ]

// Recreate state from patches
const recreated = applyPatches(state, patches);
console.log(JSON.stringify(recreated) === JSON.stringify(nextState)); // true

// Undo changes with inverse patches
const reverted = applyPatches(nextState, inversePatches);
console.log(JSON.stringify(reverted) === JSON.stringify(state)); // true
```

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

### Craft function returning new value directly

Source: https://github.com/sylphxltd/craft/blob/main/README.md

Shows that a producer can return a completely new object instead of mutating the draft, allowing explicit state replacement.

```TypeScript
const nextState = craft(currentState, (draft) => {
  return { ...draft, count: 100 };
});
```

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

### Control Automatic Freezing (TypeScript)

Source: https://github.com/sylphxltd/craft/blob/main/README.md

Shows how to configure the automatic freezing of state results using the `setAutoFreeze` function. Disabling auto-freeze can offer performance benefits in scenarios where freezing is not strictly necessary.

```typescript
import { setAutoFreeze } from "@sylphx/craft";

// Disable auto-freeze for performance
setAutoFreeze(false);
```

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

### Create reusable updaters with crafted function

Source: https://context7.com/sylphxltd/craft/llms.txt

The crafted function creates reusable updater functions by currying the craft function. These updaters can be applied to different states and composed together. This approach promotes functional programming patterns and code reusability.

```typescript
import { crafted } from "@sylphx/craft";

interface State {
  count: number;
  name: string;
}

// Create reusable updaters
const increment = crafted((draft: State) => {
  draft.count++;
});

const setName = crafted((draft: State) => {
  draft.name = "Bob";
});

// Apply updaters to different states
const state1 = { count: 0, name: "Alice" };
const state2 = increment(state1); // { count: 1, name: "Alice" }
const state3 = increment(state2); // { count: 2, name: "Alice" }
const state4 = setName(state3); // { count: 2, name: "Bob" }

console.log(state1); // { count: 0, name: "Alice" }
console.log(state4); // { count: 2, name: "Bob" }
```

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

### Delete Properties/Elements using `nothing` (TypeScript)

Source: https://github.com/sylphxltd/craft/blob/main/README.md

Demonstrates the use of the `nothing` symbol in Craft to effectively delete object properties or remove elements from arrays. This provides a clear and concise way to handle removals within the draft state.

```typescript
import { craft, nothing } from "@sylphx/craft";

// Delete object property
const next = craft(state, (draft) => {
  draft.obsoleteField = nothing;
});

// Remove array elements
const next = craft(state, (draft) => {
  draft.items[2] = nothing; // Remove 3rd element
});

// Remove multiple array elements
const next = craft(state, (draft) => {
  draft.todos.forEach((todo, i) => {
    if (todo.done) {
      draft.todos[i] = nothing; // Remove completed todos
    }
  });
});
```

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

### TypeScript Type Casting Utilities (TypeScript)

Source: https://github.com/sylphxltd/craft/blob/main/README.md

Introduces TypeScript utility functions `castDraft` and `castImmutable` for type casting between draft and immutable states. These are primarily for type safety and do not perform runtime conversions.

```typescript
import { castDraft, castImmutable } from "@sylphx/craft";

// Cast immutable to draft (type-only)
const draft = castDraft(immutableState);

// Cast mutable to immutable (type-only)
const immutable = castImmutable(mutableState);
```

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

### Reusable updater with crafted

Source: https://github.com/sylphxltd/craft/blob/main/README.md

Creates a curried updater function using `crafted` that can be applied repeatedly to different state objects.

```TypeScript
const increment = crafted((draft: State) => {
  draft.count++;
});

const state1 = { count: 0 };
const state2 = increment(state1); // { count: 1 }
const state3 = increment(state2); // { count: 2 }
```

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

### Retrieve original value from draft with original

Source: https://github.com/sylphxltd/craft/blob/main/README.md

Shows how to obtain the original immutable value underlying a draft using the `original` utility, useful for comparisons.

```TypeScript
craft(state, (draft => {
  draft.count = 10;

  console.log(draft.count);             // 10 (current)
  console.log(original(draft)?.count);  // 0 (original)
});
```

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

### Create immutable state with craft function

Source: https://context7.com/sylphxltd/craft/llms.txt

The craft function applies mutations to a draft state and returns a new immutable state. It maintains structural sharing for performance by only copying changed parts of the state tree. The base state remains unchanged after the operation.

```typescript
import { craft } from "@sylphx/craft";

const baseState = {
  user: { name: "Alice", age: 25 },
  todos: [
    { id: 1, text: "Learn Craft", done: false },
    { id: 2, text: "Use Craft", done: false }
  ]
};

// Apply mutations to create new state
const nextState = craft(baseState, (draft) => {
  draft.user.age = 26;
  draft.todos[0].done = true;
  draft.todos.push({ id: 3, text: "Master Craft", done: false });
});

// Original state unchanged
console.log(baseState.user.age); // 25
console.log(baseState.todos.length); // 2

// New state has updates
console.log(nextState.user.age); // 26
console.log(nextState.todos.length); // 3

// Structural sharing - unchanged references preserved
console.log(baseState.todos[1] === nextState.todos[1]); // true
```

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

### Set Use Strict Shallow Copy (TypeScript)

Source: https://context7.com/sylphxltd/craft/llms.txt

This function enables strict shallow copying, including non-enumerable properties during state updates. It utilizes the `craft` function from `@sylphx/craft` to perform immutable updates, demonstrating the impact of strict mode on property visibility.

```typescript
import { setUseStrictShallowCopy, craft } from "@sylphx/craft";

const state = { count: 0 };
Object.defineProperty(state, "hidden", {
  value: "secret",
  enumerable: false
});

// Standard mode (default) - ignores non-enumerable
setUseStrictShallowCopy(false);
const next1 = craft(state, (draft) => {
  draft.count++;
});

console.log((next1 as any).hidden); // undefined

// Strict mode - copies non-enumerable properties
setUseStrictShallowCopy(true);
const next2 = craft(state, (draft) => {
  draft.count++;
});

console.log((next2 as any).hidden); // "secret"
```

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

### Manual draft control with createDraft/finishDraft

Source: https://context7.com/sylphxltd/craft/llms.txt

Use createDraft and finishDraft for advanced scenarios requiring manual control over the draft lifecycle, such as async operations. This pattern allows making both synchronous and asynchronous changes to a draft before finalizing it into an immutable state.

```typescript
import { createDraft, finishDraft } from "@sylphx/craft";

interface AppState {
  user: { name: string; email: string } | null;
  count: number;
  loading: boolean;
}

const state: AppState = {
  user: null,
  count: 0,
  loading: false
};

async function updateWithAPI(baseState: AppState) {
  const draft = createDraft(baseState);

  // Make synchronous changes
  draft.loading = true;
  draft.count++;

  // Make async changes
  const userData = await fetch("/api/user").then(r => r.json());
  draft.user = userData;
  draft.loading = false;

  // Finalize when ready
  return finishDraft(draft);
}

// Usage
const nextState = await updateWithAPI(state);
console.log(nextState.user); // { name: "Alice", email: "alice@example.com" }
console.log(nextState.count); // 1
console.log(nextState.loading); // false
```

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

### Type Safety in Craft State Updates

Source: https://github.com/sylphxltd/craft/blob/main/README.md

Illustrates Craft's full TypeScript inference for state interfaces, preventing invalid assignments like string to number or accessing nonexistent properties. Inputs are typed state objects; outputs are immutable updates with compile-time checks. Depends on TypeScript; no runtime overhead for types.

```typescript
interface State {
  count: number;
  user: {
    name: string;
    age: number;
  };
}

const state: State = { count: 0, user: { name: "Alice", age: 25 } };

craft(state, (draft) => {
  draft.count = "invalid"; // ❌ Type error
  draft.user.age = 26; // ✅ OK
  draft.nonexistent = true; // ❌ Type error
});
```

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

### Access Original Value with original (TypeScript)

Source: https://context7.com/sylphxltd/craft/llms.txt

The original function accesses the original base value from within a producer function. It requires importing from @sylphx/craft and is used inside a craft producer. Returns the original state object for comparison or storage, with no access outside producers.

```typescript
import { craft, original } from "@sylphx/craft";

interface State {
  count: number;
  lastValue: number;
}

const state: State = { count: 10, lastValue: 0 };

const next = craft(state, (draft) => {
  const baseValue = original(draft);

  // Store previous value before updating
  if (baseValue) {
    draft.lastValue = baseValue.count;
  }

  draft.count = 20;
});

console.log(next);
// { count: 20, lastValue: 10 }
```

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

### Use Strict Shallow Copy (TypeScript)

Source: https://github.com/sylphxltd/craft/blob/main/README.md

Enables strict shallow copy behavior with `setUseStrictShallowCopy`. When enabled, it ensures that non-enumerable properties are included during shallow copies, potentially affecting how state is duplicated.

```typescript
import { setUseStrictShallowCopy } from "@sylphx/craft";

setUseStrictShallowCopy(true);
```

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

### Manually Freeze Object (TypeScript)

Source: https://github.com/sylphxltd/craft/blob/main/README.md

Provides a utility function `freeze` to manually freeze an object, either shallowly or deeply. This can be used to ensure immutability for specific objects outside of the standard Craft production process.

```typescript
import { freeze } from "@sylphx/craft";

const frozen = freeze(myObject);
const deepFrozen = freeze(myObject, true);
```

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

### Configure Auto-Freezing with setAutoFreeze in TypeScript

Source: https://context7.com/sylphxltd/craft/llms.txt

setAutoFreeze toggles automatic Object.freeze on produced states for immutability in development vs performance in production. Imported from @sylphx/craft, it takes a boolean; affects subsequent craft calls; no direct inputs/outputs but impacts state mutability; limitation is global setting affecting all uses.

```typescript
import { setAutoFreeze, craft } from "@sylphx/craft";

// Disable auto-freeze for performance in production
setAutoFreeze(false);

const state = { count: 0 };
const next = craft(state, (draft) => {
  draft.count++;
});

console.log(Object.isFrozen(next)); // false

// Re-enable for development debugging
setAutoFreeze(true);

const next2 = craft(next, (draft) => {
  draft.count++;
});

console.log(Object.isFrozen(next2)); // true
```

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

### Check Draft Proxy with isDraft (TypeScript)

Source: https://context7.com/sylphxltd/craft/llms.txt

The isDraft function checks if a value is a draft proxy created by the Craft library. It imports from @sylphx/craft and takes any value as input. Returns a boolean indicating if it's a draft, but cannot detect drafts on primitive values.

```typescript
import { craft, isDraft } from "@sylphx/craft";

const state = { count: 0 };

console.log(isDraft(state)); // false

craft(state, (draft) => {
  console.log(isDraft(draft)); // true
  console.log(isDraft(draft.count)); // false (primitives are not drafts)
});
```

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

### Freeze Object (TypeScript)

Source: https://context7.com/sylphxltd/craft/llms.txt

This function freezes an object, either shallowly or deeply, to ensure immutability. It uses `Object.isFrozen` to verify the freezing status and demonstrates the difference between shallow and deep freezing for nested objects.

```typescript
import { freeze } from "@sylphx/craft";

const mutableState = {
  user: { name: "Alice", age: 25 },
  items: [1, 2, 3]
};

// Shallow freeze
const shallowFrozen = freeze(mutableState);
console.log(Object.isFrozen(shallowFrozen)); // true
console.log(Object.isFrozen(shallowFrozen.user)); // false

// Deep freeze
const deepFrozen = freeze({ ...mutableState }, true);
console.log(Object.isFrozen(deepFrozen)); // true
console.log(Object.isFrozen(deepFrozen.user)); // true
console.log(Object.isFrozen(deepFrozen.items)); // true
```

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

### Check draft status with isDraft

Source: https://github.com/sylphxltd/craft/blob/main/README.md

Uses the `isDraft` utility to determine whether a given value is a draft created by Craft.

```TypeScript
import { craft, isDraft } from "@sylphx/craft";

craft(state, (draft) => {
  console.log(isDraft(draft)); // true
  console.log(isDraft(state)); // false
});
```

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

### Delete Properties with nothing Symbol in TypeScript

Source: https://context7.com/sylphxltd/craft/llms.txt

The nothing symbol, used with craft, removes object properties or array elements without leaving undefined values. Imported from @sylphx/craft, it takes a base state and draft mutator; inputs are state and producer function assigning nothing; outputs a cleaned state; ideal for deletions but requires type assertion as any.

```typescript
import { craft, nothing } from "@sylphx/craft";

interface State {
  name: string;
  obsoleteField?: string;
  items: string[];
  todos: Array<{ id: number; text: string; done: boolean }>;
}

const state: State = {
  name: "App",
  obsoleteField: "old data",
  items: ["a", "b", "c", "d"],
  todos: [
    { id: 1, text: "Buy milk", done: true },
    { id: 2, text: "Write code", done: false },
    { id: 3, text: "Deploy", done: true }
  ]
};

// Delete object properties
const next1 = craft(state, (draft) => {
  draft.obsoleteField = nothing as any;
});

console.log("obsoleteField" in next1); // false

// Remove specific array elements
const next2 = craft(state, (draft) => {
  draft.items[1] = nothing as any; // Remove "b"
});

console.log(next2.items); // ["a", "c", "d"]

// Remove completed todos
const next3 = craft(state, (draft) => {
  draft.todos.forEach((todo, index) => {
    if (todo.done) {
      draft.todos[index] = nothing as any;
    }
  });
});

console.log(next3.todos);
// [{ id: 2, text: "Write code", done: false }]
```

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