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8a9bc9a | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 | # 🌊 defu
Assign default properties, recursively. Lightweight and Fast.
[![npm version][npm-version-src]][npm-version-href]
[![npm downloads][npm-downloads-src]][npm-downloads-href]
[![bundle][bundle-src]][bundle-href]
[![Codecov][codecov-src]][codecov-href]
[![License][license-src]][license-href]
## Install
Install package:
```bash
# yarn
yarn add defu
# npm
npm install defu
# pnpm
pnpm install defu
```
## Usage
```js
import { defu } from "defu";
const options = defu(object, ...defaults);
```
Leftmost arguments have more priority when assigning defaults.
### Arguments
- **object (Object):** The destination object.
- **source (Object):** The source object.
```js
import { defu } from "defu";
console.log(defu({ a: { b: 2 } }, { a: { b: 1, c: 3 } }));
// => { a: { b: 2, c: 3 } }
```
### Using with CommonJS
```js
const { defu } = require("defu");
```
## Custom Merger
Sometimes default merging strategy is not desirable. Using `createDefu` we can create a custom instance with different merging strategy.
This function accepts `obj` (source object), `key` and `value` (current value) and should return `true` if applied custom merging.
**Example:** Sum numbers instead of overriding
```js
import { createDefu } from "defu";
const ext = createDefu((obj, key, value) => {
if (typeof obj[key] === "number" && typeof value === "number") {
obj[key] += value;
return true;
}
});
ext({ cost: 15 }, { cost: 10 }); // { cost: 25 }
```
## Function Merger
Using `defuFn`, if user provided a function, it will be called with default value instead of merging.
It can be useful for default values manipulation.
**Example:** Filter some items from defaults (array) and add 20 to the count default value.
```js
import { defuFn } from "defu";
defuFn(
{
ignore: (val) => val.filter((item) => item !== "dist"),
count: (count) => count + 20,
},
{
ignore: ["node_modules", "dist"],
count: 10,
},
);
/*
{
ignore: ['node_modules'],
count: 30
}
*/
```
**Note:** if the default value is not defined, the function defined won't be called and kept as value.
## Array Function Merger
`defuArrayFn` is similar to `defuFn` but **only applies to array values defined in defaults**.
**Example:** Filter some items from defaults (array) and add 20 to the count default value.
```js
import { defuArrayFn } from 'defu'
defuArrayFn({
ignore: (val) => val.filter(i => i !== 'dist'),
count: () => 20
}, {
ignore: [
'node_modules',
'dist'
],
count: 10
})
/*
{
ignore: ['node_modules'],
count: () => 20
}
*/
```
**Note:** the function is called only if the value defined in defaults is an aray.
### Remarks
- `object` and `defaults` are not modified
- Nullish values ([`null`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/null) and [`undefined`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/undefined)) are skipped. Please use [defaults-deep](https://www.npmjs.com/package/defaults-deep) or [omit-deep](http://npmjs.com/package/omit-deep) or [lodash.defaultsdeep](https://www.npmjs.com/package/lodash.defaultsdeep) if you need to preserve or different behavior.
- Assignment of `__proto__` and `constructor` keys will be skipped to prevent security issues with object pollution.
- Will concat `array` values (if default property is defined)
```js
console.log(defu({ array: ["b", "c"] }, { array: ["a"] }));
// => { array: ['b', 'c', 'a'] }
```
## Type
We expose `Defu` as a type utility to return a merged type that follows the rules that defu follows.
```js
import type { Defu } from 'defu'
type Options = Defu<{ foo: 'bar' }, [{}, { bar: 'baz' }, { something: 42 }]>
// returns { foo: 'bar', bar: 'baz', 'something': 42 }
```
## License
MIT. Made with 💖
<!-- Refs -->
[npm-version-src]: https://img.shields.io/npm/v/defu?style=flat&colorA=18181B&colorB=F0DB4F
[npm-version-href]: https://npmjs.com/package/defu
[npm-downloads-src]: https://img.shields.io/npm/dm/defu?style=flat&colorA=18181B&colorB=F0DB4F
[npm-downloads-href]: https://npmjs.com/package/defu
[codecov-src]: https://img.shields.io/codecov/c/gh/unjs/defu/main?style=flat&colorA=18181B&colorB=F0DB4F
[codecov-href]: https://codecov.io/gh/unjs/defu
[bundle-src]: https://img.shields.io/bundlephobia/minzip/defu?style=flat&colorA=18181B&colorB=F0DB4F
[bundle-href]: https://bundlephobia.com/result?p=defu
[license-src]: https://img.shields.io/github/license/unjs/defu.svg?style=flat&colorA=18181B&colorB=F0DB4F
[license-href]: https://github.com/unjs/defu/blob/main/LICENSE
|