pretty-var-export

Export any value to valid and equivalent JavaScript code. Uses syntax coloring for debugging from the cli.

npm install pretty-var-export

Usage

const pretty = require('pretty-var-export');

// return string suitable for logging
console.log(pretty(myValue));

// OR prettify and log
pretty.log(myValue);

Note that coloring can be disabled with pretty.colors.disable().

Example output

Customization

Add handler
Remove handler
Custom indent
Custom colors
Custom display options
Custom labels

Add handler

Add custom handlers for formatting.

For example, show NaN as a different color than numbers:

const pretty = require('pretty-var-export');

// each handler must have a test and format method
pretty.handlers.add('nan', {
    test: isNaN,
    format: () => pretty.colors.palette.cyan('NaN'),
});

// reset to default list
pretty.handlers.reset();

Remove handler

You can remove handlers by name.

const pretty = require('pretty-var-export');

// see below for list of names
pretty.handlers.remove('nan');

// reset to default list
pretty.handlers.reset();

Default handler names:

arguments
Array
BigInt
Boolean
Date
Error
Function
Map
null
Number
Object
Promise
RegExp
Set
String
Symbol
TypedArray
undefined
URL
URLSearchParams
WeakMap
WeakSet

Custom indent

By default, indentation is 2 spaces.

const pretty = require('pretty-var-export');

pretty.options.indent = 4;      // 4 spaces
pretty.options.indent = '    '; // 4 spaces
pretty.options.indent = '\t';   // tab

Custom colors

Colors come from the ansi-colors npm module.

Formats include the following:

boolean for true and false (default yellow)
comment for comments (default gray)
constructor for instantiation (default blue)
escape for string escapes (default yellowBright)
null for null (default yellow)
number for numbers, NaN, Infinity (default red)
property for object property names (default cyan)
regexp for bodies of regular expressions (default blue)
string for strings (default green)
symbol for quotes, braces, parens, commas, colons (default white)
undefined for undefined (default yellow)

const pretty = require('pretty-var-export');

// existing color functions from the ansi-colors npm package
pretty.colors.symbol = pretty.colors.palette.blueBright;

// use any other function
pretty.colors.string = chalk.green;

// disable all coloring
pretty.colors.disable();

// reset to default colors and re-enable coloring
pretty.colors.reset();

Custom display options

There are a few options that can change display. Below are defaults.

const pretty = require('pretty-var-export');
 
// if true, show function bodies
pretty.options.showFunctionBody = false;

// the max length for strings
pretty.options.maxStringLength = 1024 * 4;

// max number of items to list
pretty.options.maxListItems = 100;

// output multi-line strings with backticks
pretty.options.preferBackticks = true;
 
// quote style for default strings (single, double or backtick)
pretty.options.quoteStyle = 'double';
 
// reset to defaults
pretty.options.reset();

Custom labels

Labels can be changed or translated.

const pretty = require('pretty-var-export');

// defaults
pretty.labels.circularReference = 'Circular Reference';
pretty.labels.codeOmitted = 'Code Omitted';
pretty.labels.itemsUnknown = 'Items Unknown';

// reset to defaults
pretty.labels.reset();

Changelog

See CHANGELOG.md

Contributing

Please open a ticket or PR on GitHub.

License

MIT License

npm