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# pretty-format [![Travis build status](http://img.shields.io/travis/thejameskyle/pretty-format.svg?style=flat)](https://travis-ci.org/thejameskyle/pretty-format)
> Stringify any JavaScript value.
- Supports [all built-in JavaScript types](#type-support)
- [Blazingly fast](https://gist.github.com/thejameskyle/2b04ffe4941aafa8f970de077843a8fd) (similar performance to v8's `JSON.stringify` and significantly faster than Node's `util.format`)
- Plugin system for extending with custom types (i.e. [`ReactTestComponent`](#reacttestcomponent-plugin))
## Installation
```sh
$ npm install pretty-format
```
## Usage
```js
var prettyFormat = require('pretty-format');
var obj = { property: {} };
obj.circularReference = obj;
obj[Symbol('foo')] = 'foo';
obj.map = new Map();
obj.map.set('prop', 'value');
obj.array = [1, NaN, Infinity];
console.log(prettyFormat(obj));
```
**Result:**
```js
Object {
"property": Object {},
"circularReference": [Circular],
"map": Map {
"prop" => "value"
},
"array": Array [
1,
NaN,
Infinity
],
Symbol(foo): "foo"
}
```
#### Type Support
`Object`, `Array`, `ArrayBuffer`, `DataView`, `Float32Array`, `Float64Array`, `Int8Array`, `Int16Array`, `Int32Array`, `Uint8Array`, `Uint8ClampedArray`, `Uint16Array`, `Uint32Array`, `arguments`, `Boolean`, `Date`, `Error`, `Function`, `Infinity`, `Map`, `NaN`, `null`, `Number`, `RegExp`, `Set`, `String`, `Symbol`, `undefined`, `WeakMap`, `WeakSet`
### Plugins
Pretty format also supports adding plugins:
```js
var fooPlugin = {
test: function(val) {
return val && val.hasOwnProperty('foo');
},
print: function(val, print, indent) {
return 'Foo: ' + print(val.foo);
}
};
var obj = { foo: { bar: {} } };
prettyFormat(obj, {
plugins: [fooPlugin]
});
// Foo: Object {
// "bar": Object {}
// }
```
#### `ReactTestComponent` plugin
```js
var prettyFormat = require('pretty-format');
var reactPlugin = require('pretty-format/plugins/ReactTestComponent');
var React = require('react');
var renderer = require('react/lib/ReactTestRenderer');
var jsx = React.createElement('h1', null, 'Hello World');
prettyFormat(renderer.create(jsx).toJSON(), {
plugins: [reactPlugin]
});
// <h1>
// Hello World
// </h1>
```