Package Exports

pretty-format
pretty-format/build/collections
pretty-format/build/plugins/lib/markup
pretty-format/build/plugins/lib/markup.js

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (pretty-format) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

pretty-format

Stringify any JavaScript value.

Supports all built-in JavaScript types
- primitive types: Boolean, null, Number, String, Symbol, undefined
- other non-collection types: Date, Error, Function, RegExp
- collection types:
  - arguments, Array, ArrayBuffer, DataView, Float32Array, Float64Array, Int8Array, Int16Array, Int32Array, Uint8Array, Uint8ClampedArray, Uint16Array, Uint32Array,
  - Map, Set, WeakMap, WeakSet
  - Object
Blazingly fast
- similar performance to JSON.stringify in v8
- significantly faster than util.format in Node.js
Serialize application-specific data types with built-in or user-defined plugins

Installation

$ yarn add pretty-format

Usage

const prettyFormat = require('pretty-format'); // CommonJS

import prettyFormat from 'pretty-format'; // ES2015 modules

const val = {object: {}};
val.circularReference = val;
val[Symbol('foo')] = 'foo';
val.map = new Map([['prop', 'value']]);
val.array = [-0, Infinity, NaN];

console.log(prettyFormat(val));
/*
Object {
  "array": Array [
    -0,
    Infinity,
    NaN,
  ],
  "circularReference": [Circular],
  "map": Map {
    "prop" => "value",
  },
  "object": Object {},
  Symbol(foo): "foo",
}
*/

Usage with options

function onClick() {}

console.log(prettyFormat(onClick));
/*
[Function onClick]
*/

const options = {
  printFunctionName: false,
};
console.log(prettyFormat(onClick, options));
/*
[Function]
*/

key	type	default	description
`callToJSON`	`boolean`	`true`	call `toJSON` method (if it exists) on objects
`escapeRegex`	`boolean`	`false`	escape special characters in regular expressions
`highlight`	`boolean`	`false`	highlight syntax with colors in terminal (some plugins)
`indent`	`number`	`2`	spaces in each level of indentation
`maxDepth`	`number`	`Infinity`	levels to print in arrays, objects, elements, and so on
`min`	`boolean`	`false`	minimize added space: no indentation nor line breaks
`plugins`	`array`	`[]`	plugins to serialize application-specific data types
`printFunctionName`	`boolean`	`true`	include or omit the name of a function
`theme`	`object`		colors to highlight syntax in terminal

Property values of theme are from ansi-styles colors

const DEFAULT_THEME = {
  comment: 'gray',
  content: 'reset',
  prop: 'yellow',
  tag: 'cyan',
  value: 'green',
};

Usage with plugins

The pretty-format package provides some built-in plugins, including:

ReactElement for elements from react
ReactTestComponent for test objects from react-test-renderer

// CommonJS
const prettyFormat = require('pretty-format');
const ReactElement = prettyFormat.plugins.ReactElement;
const ReactTestComponent = prettyFormat.plugins.ReactTestComponent;

const React = require('react');
const renderer = require('react-test-renderer');

// ES2015 modules and destructuring assignment
import prettyFormat from 'pretty-format';
const {ReactElement, ReactTestComponent} = prettyFormat.plugins;

import React from 'react';
import renderer from 'react-test-renderer';

const onClick = () => {};
const element = React.createElement('button', {onClick}, 'Hello World');

const formatted1 = prettyFormat(element, {
  plugins: [ReactElement],
  printFunctionName: false,
});
const formatted2 = prettyFormat(renderer.create(element).toJSON(), {
  plugins: [ReactTestComponent],
  printFunctionName: false,
});
/*
<button
  onClick=[Function]
>
  Hello World
</button>
*/

Plugins

Pretty format also supports adding plugins:

const fooPlugin = {
  test(val) {
    return val && val.hasOwnProperty('foo');
  },
  print(val, print, indent) {
    return 'Foo: ' + print(val.foo);
  },
};

const obj = {foo: {bar: {}}};

prettyFormat(obj, {
  plugins: [fooPlugin],
});
// Foo: Object {
//   "bar": Object {}
// }