Transforms deeply nested object, array, Map, and Set keys between common case formats while preserving TypeScript type safety
npm install deep-case-crafterš DeepCaseCrafter is a TypeScript utility that transforms deeply nested object keys into different case formats while maintaining type safety. It supports objects, arrays, Maps, and Sets and allows custom recursion depth.
- š Automatically converts keys to camelCase, PascalCase, snake_case, and kebab-case.
- š Works with deeply nested structures, including objects, arrays, Maps, and Sets.
- ā
Maintains TypeScript type inference for better auto-completion.
- š Preserves special keys (__, --, leading numbers, special characters).
- ā” Performance-optimized with minimal overhead.
- š Configurable recursion depth (default: 3).
``bash`
npm install deep-case-crafter
---
`typescript
import transform from 'deep-case-crafter';
const input = { user_id: 1, first_name: 'John' };
const result = transform(input);
console.log(result);
// Output: { userId: 1, firstName: 'John' }
`
_(Automatically converts from snake_case to camelCase)_
---
`typescript
const input = { user_id: 1, first_name: 'John' };
const pascalCaseResult = transform(input, { targetCase: 'pascal' });
console.log(pascalCaseResult);
// Output: { UserId: 1, FirstName: 'John' }
const kebabCaseResult = transform(input, { targetCase: 'kebab' });
console.log(kebabCaseResult);
// Output: { "user-id": 1, "first-name": "John" }
`
---
_TypeScript automatically infers key changes when sourceCase is set._
`typescript
const input = { user_id: 1, first_name: 'John' };
const result = transform(input, { targetCase: 'camel', sourceCase: 'snake' });
console.log(result);
// Output: { userId: 1, firstName: 'John' }
`
---
`typescript
const nestedInput = {
user_info: { first_name: 'John', last_name: 'Doe' },
posts: [{ post_id: 1, post_title: 'Hello' }],
};
const transformed = transform(nestedInput, {
targetCase: 'camel',
sourceCase: 'snake',
});
console.log(transformed);
// Output:
// {
// userInfo: { firstName: 'John', lastName: 'Doe' },
// posts: [{ postId: 1, postTitle: 'Hello' }]
// }
`
---
`typescript
const mapInput = new Map([
['user_id', 1],
['first_name', 'John'],
]);
const result = transform(mapInput, {
targetCase: 'camel',
sourceCase: 'snake',
});
console.log(result.get('userId')); // 1
console.log(result.get('firstName')); // 'John'
`
---
`typescript
const setInput = new Set(['user_id', 'first_name']);
const result = transform(setInput, {
targetCase: 'camel',
sourceCase: 'snake',
});
console.log(result); // Set { 'userId', 'firstName' }
`
---
- data: The data structure to transform (object, array, Map, or Set).targetCase
- options:
- (optional): 'camel' | 'snake' | 'pascal' | 'kebab' (default: 'camel')sourceCase
- (optional): Required for TypeScript inference ('snake' | 'camel' | 'pascal' | 'kebab').depth
- (optional): Recursion depth (default: 3, use Infinity for full recursion).
---
If you want to specify the output type explicitly (for example, when you know the exact shape you want), you can use the following overload:
`typescript`
const result = transform
const typedResult: Output = result; // TypeScript will enforce Output type here
Note:
- When using this overload, you cannot pass sourceCase in the options. If you do, TypeScript will show an error:sourceCase
> Object literal may only specify known properties, and 'sourceCase' does not exist in type 'Omit
- This overload is useful when you want to take full control of the output type, but type safety between input, options, and output is not enforced by the library.
- If you want to use and benefit from type inference, use the standard overload:
`typescript`
const result = transform(obj, { targetCase: 'camel', sourceCase: 'snake' }); // Output type is inferred
---
- Keys that start with special characters or numbers are not transformed.
- Keys with __ or -- remain unchanged.
- Numbers at the end of keys are preserved.
---
DeepCaseCrafter is optimized for speed and efficiency:
`plaintext`
Transform Deep Object (Depth 5, Width 10)
x 361,538 ops/sec Ā±0.12% (91 runs sampled)
---
1. Fork the repository.
2. Create a new branch (feature/my-feature).git commit -m "Add new feature"`).
3. Commit your changes (
4. Submit a pull request š.
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MIT
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