https://github.com/mcmath/deep-map-keys
Transforms nested keys of complex objects
https://github.com/mcmath/deep-map-keys
Last synced: 10 months ago
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Transforms nested keys of complex objects
- Host: GitHub
- URL: https://github.com/mcmath/deep-map-keys
- Owner: mcmath
- License: mit
- Created: 2016-06-14T06:55:19.000Z (almost 10 years ago)
- Default Branch: master
- Last Pushed: 2022-10-21T23:04:04.000Z (over 3 years ago)
- Last Synced: 2025-03-25T12:11:04.525Z (about 1 year ago)
- Language: TypeScript
- Homepage:
- Size: 39.1 KB
- Stars: 21
- Watchers: 3
- Forks: 6
- Open Issues: 6
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# Deep Map Keys
[![Version][version-badge]][npm]
[![License][license-badge]][license]
[![Build][build-badge]][travis]
[![Coverage][coverage-badge]][coveralls]
[Install](#install) | [Usage](#usage) | [API](#api) | [TypeScript](#typescript) | [License](#license)
**Deep Map Keys** recurses through an object and transforms its keys – and
the keys of any nested objects – according to some function. Circular
references are supported.
To transform the *values* of an object rather than its keys, use
[Deep Map][deep-map].
## Install
Install Deep Map Keys via [npm][npm].
```sh
npm install --save deep-map-keys
```
## Usage
Suppose we want to change the keys of an object from [snake case][snake-case] to
[camel case][camel-case]. We can do something like this:
```js
const deepMapKeys = require('deep-map-keys');
let comment = {
comment_id: 42,
user_id: 1024,
user_name: 'Mufasa',
content: 'You deliberately disobeyed me.',
viewed_by: [
{ user_id: 3820, user_name: 'Rafiki' },
{ user_id: 8391, user_name: 'Zazu' }
]
};
function snakeToCamel(key) {
return key.replace(/_(\w)/g, (match, char) => char.toUpperCase());
}
let result = deepMapKeys(comment, snakeToCamel);
```
And the result will look like this:
```js
{
commentId: 42,
userId: 1024,
userName: 'Mufasa',
content: 'You deliberately disobeyed me.',
viewedBy: [
{ userId: 3820, userName: 'Rafiki' },
{ userId: 8391, userName: 'Zazu' }
]
}
```
## API
#### `deepMapKeys(object, mapFn, [options])`
#### Parameters
Param
Type
Description
object
any
The object whose keys are to be transformed. Typically, this will be
a complex object containing other nested objects. This object may be an
Array, in which case the keys of any objects it
contains will be transformed. The object may contain circular
references.
mapFn
function
The function used to transform each key. The function is
called with two arguments:
-
key <string>
The key being transformed
-
value <any>
The value of the node whose key is being transformed
The return value determines the new name of the key, and must therefore
be a string.
[options]
object
An optional options object. The following option is accepted:
-
thisArg <any=undefined>
Sets the value of
this
withinmapFn()
#### Returns
Returns a new object.
## TypeScript
[TypeScript][typescript] declarations are included in the package. Just import
the module, and things will just work.
The shape of the returned object cannot be inferred from the inputs; however it
can be defined by passing a single type argument.
```ts
interface Result {
userName: string;
}
let result = deepMapKeys({user_name: 'Pumbaa'}, snakeToCamel);
let name = result.userName; // Everything is OK :)
```
## License
Copyright © 2016–2019 Akim McMath. Licensed under the [MIT License][license].
[version-badge]: https://img.shields.io/npm/v/deep-map-keys.svg?style=flat-square
[license-badge]: https://img.shields.io/npm/l/deep-map-keys.svg?style=flat-square
[build-badge]: https://img.shields.io/travis/mcmath/deep-map-keys/master.svg?style=flat-square
[coverage-badge]: https://img.shields.io/coveralls/mcmath/deep-map-keys/master.svg?style=flat-square&service=github
[npm]: https://www.npmjs.com/package/deep-map-keys
[license]: LICENSE
[travis]: https://travis-ci.org/mcmath/deep-map-keys
[coveralls]: https://coveralls.io/github/mcmath/deep-map-keys?branch=master
[deep-map]: https://github.com/mcmath/deep-map
[snake-case]: https://en.wikipedia.org/wiki/Snake_case
[camel-case]: https://en.wikipedia.org/wiki/CamelCase
[typescript]: http://www.typescriptlang.org/