135 lines
3.4 KiB
Markdown
135 lines
3.4 KiB
Markdown
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# pretty-format
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> Stringify any JavaScript value.
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- Supports [all built-in JavaScript types](#type-support)
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- [Blazingly fast](https://gist.github.com/thejameskyle/2b04ffe4941aafa8f970de077843a8fd) (similar performance to v8's `JSON.stringify` and significantly faster than Node's `util.format`)
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- Plugin system for extending with custom types (i.e. [`ReactTestComponent`](#reacttestcomponent-plugin))
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## Installation
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```sh
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$ yarn add pretty-format
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```
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## Usage
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```js
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const prettyFormat = require('pretty-format');
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var obj = { property: {} };
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obj.circularReference = obj;
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obj[Symbol('foo')] = 'foo';
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obj.map = new Map();
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obj.map.set('prop', 'value');
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obj.array = [1, NaN, Infinity];
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console.log(prettyFormat(obj));
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```
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**Result:**
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```js
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Object {
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"property": Object {},
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"circularReference": [Circular],
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"map": Map {
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"prop" => "value"
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},
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"array": Array [
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1,
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NaN,
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Infinity
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],
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Symbol(foo): "foo"
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}
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```
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#### Type Support
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`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`
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### API
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```js
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console.log(prettyFormat(object));
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console.log(prettyFormat(object, options));
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```
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Options:
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* **`callToJSON`**<br>
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Type: `boolean`, default: `true`<br>
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Call `toJSON()` on passed object.
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* **`indent`**<br>
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Type: `number`, default: `2`<br>
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Number of spaces for indentation.
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* **`maxDepth`**<br>
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Type: `number`, default: `Infinity`<br>
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Print only this number of levels.
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* **`min`**<br>
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Type: `boolean`, default: `false`<br>
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Print without whitespace.
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* **`plugins`**<br>
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Type: `array`, default: `[]`<br>
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Plugins (see the next section).
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* **`printFunctionName`**<br>
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Type: `boolean`, default: `true`<br>
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Print function names or just `[Function]`.
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* **`escapeRegex`**<br>
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Type: `boolean`, default: `false`<br>
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Escape special characters in regular expressions.
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* **`highlight`**<br>
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Type: `boolean`, default: `false`<br>
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Highlight syntax for terminal (works only with `ReactTestComponent` and `ReactElement` plugins.
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* **`theme`**<br>
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Type: `object`, default: `{tag: 'cyan', content: 'reset'...}`<br>
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Syntax highlight theme.<br>
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Uses [ansi-styles colors](https://github.com/chalk/ansi-styles#colors) + `reset` for no color.<br>
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Available types: `tag`, `content`, `prop` and `value`.
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### Plugins
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Pretty format also supports adding plugins:
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```js
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const fooPlugin = {
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test(val) {
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return val && val.hasOwnProperty('foo');
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},
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print(val, print, indent) {
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return 'Foo: ' + print(val.foo);
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}
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};
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const obj = {foo: {bar: {}}};
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prettyFormat(obj, {
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plugins: [fooPlugin]
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});
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// Foo: Object {
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// "bar": Object {}
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// }
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```
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#### `ReactTestComponent` and `ReactElement` plugins
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```js
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const prettyFormat = require('pretty-format');
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const reactTestPlugin = require('pretty-format/build/plugins/ReactTestComponent');
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const reactElementPlugin = require('pretty-format/build/plugins/ReactElement');
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const React = require('react');
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const renderer = require('react-test-renderer');
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const element = React.createElement('h1', null, 'Hello World');
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prettyFormat(renderer.create(element).toJSON(), {
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plugins: [reactTestPlugin, reactElementPlugin]
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});
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// <h1>
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// Hello World
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// </h1>
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```
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