prettyoutput

Library to format js/json object into YAML style readable output. It's performance centric to be used as a logger formatter. It's currently 3 to 5 times quicker than util.inspect used by many loggers. It's available as a NodeJS library or a cli too.

Credits

This is based on the great work done on the project prettyjson

How to install

Via NPM:

1$ npm install prettyoutput

Using it

It's pretty easy to use. Just have include it in your script and call it:

1const prettyoutput = require('prettyoutput')
2
3const data = {
4  username: 'kic',
5  url: 'https://github.com/keepitcool',
6  projects: ['prettyoutput', '3m2tuio']
7}
8
9console.log(prettyoutput(data))

Output:

API

1const prettyoutput = require('prettyoutput')
2prettyoutput(data, options, indent)

Parameters are :

• {*} data : js or json object
• {Object} [options] : Optional. See options below
• {number} [indent] : Optional. Indent all output

Options are :

• {number} [indentationLength] : Length of indentation (in terms of space)
• {number} [maxDepth] : maximum sublevel of nested objects/arrays to output. Default: 3
• {boolean} [noColor] : disable colors. Default: false
• {colors} [colors] : Output colors. See below
• {boolean} [alignKeyValues] : Align key values. Default: true
• {boolean} [emptyArrayMsg] : Rendered message on empty array. Default: '(empty array)'
• {boolean} [emptyObjectMsg] : Rendered message on empty object. Default: '(empty object)'

Colors are :

• {string} [keys] : Objects keys color. Default: green
• {string} [dash] : Array prefixing dash ("- "). Default: green
• {string} [number] : Numbers color. Default: blue
• {string} [string] : Strings color. Default: no color
• {string} [true] : Boolean value 'true' color. Default: green
• {string} [false] : Boolean value 'false' color. Default: red
• {string} [null] : 'Null' color. Default: grey
• {string} [undefined] : 'Undefined' color. Default: grey

Example using options :

1const prettyoutput = require('prettyoutput')
2
3const data = {
4  username: 'kic',
5  url: 'https://github.com/keepitcool',
6  projects: ['prettyoutput', '3m2tuio']
7}
8
9const colors = {
10  keys: 'blue',
11  'null': 'red'
12}
13
14const options = {
15  noColor: true,
16  maxDepth: 5,
17  colors: colors
18};
19
20console.log(prettyoutput(data, options, 2);

Cli usage

Command line tool support file param or stdin.

Usage:

1$ prettyoutput package.json

This should output :

Command line options

It's possible to customize the output through some command line options:

1# Indent 4, max depth 5, disable colors
2$ prettyjson --indent=4 --depth=5 --noColor package.json

or

1# Indent 4, max depth 5, disable colors
2$ cat package.json | prettyjson --indent=4 --depth=5 --noColor

Benchmark

Project target logging, so performance is an issue. Currently, prettyoutput is 3 times quicker than util.inspect and 2.5 times quicker than prettyjson, the library it's inspired from.

To run benchmark, just run :

1$ node benchmark/benchmark.js

Results :

LEVELS | KEYS | LOOPS | WEIGTHS
3      | 20   | 100   | serializable: 0.9    array: 0.3    object: 0.5    multilineString: 0.3    error: 0.2

NAME         | MIN                 | MAX                 | MEAN                | TOTAL
prettyoutput | 3 ms 133 µs 526 ns  | 42 ms 563 µs 146 ns | 4 ms 365 µs 617 ns  | 436 ms 561 µs 716 ns
prettyjson   | 9 ms 615 µs 703 ns  | 21 ms 441 µs 595 ns | 11 ms 447 µs 83 ns  | 1 s 144 ms 708 µs 348 ns
util.inspect | 10 ms 839 µs 974 ns | 24 ms 332 µs 545 ns | 12 ms 526 µs 168 ns | 1 s 252 ms 616 µs 884 ns


LEVELS | KEYS | LOOPS | WEIGTHS
4      | 20   | 100   | serializable: 0.9    array: 0.3    object: 0.5    multilineString: 0.3    error: 0.2

NAME         | MIN                 | MAX                  | MEAN                 | TOTAL
prettyoutput | 29 ms 966 µs 837 ns | 102 ms 170 µs 779 ns | 39 ms 502 µs 799 ns  | 3 s 950 ms 279 µs 972 ns
prettyjson   | 86 ms 731 µs 622 ns | 159 ms 166 µs 633 ns | 107 ms 813 µs 674 ns | 10 s 781 ms 367 µs 439 ns
util.inspect | 90 ms 942 µs 290 ns | 256 ms 995 µs 418 ns | 118 ms 794 µs 343 ns | 11 s 879 ms 434 µs 322 ns


LEVELS | KEYS | LOOPS | WEIGTHS
5      | 20   | 100   | serializable: 0.9    array: 0.3    object: 0.5    multilineString: 0.3    error: 0.2

NAME         | MIN                      | MAX                      | MEAN                     | TOTAL
prettyoutput | 616 ms 495 µs 243 ns     | 1 s 602 ms 965 µs 211 ns | 768 ms 761 µs 315 ns     | 76 s 876 ms 131 µs 544 ns
prettyjson   | 1 s 294 ms 734 µs 939 ns | 1 s 686 ms 600 µs 593 ns | 1 s 490 ms 394 µs 707 ns | 149 s 39 ms 470 µs 777 ns
util.inspect | 1 s 623 ms 160 µs 631 ns | 2 s 460 ms 983 µs 994 ns | 1 s 731 ms 699 µs 847 ns | 173 s 169 ms 984 µs 758 ns

Running Tests

To run the test suite first invoke the following command within the repo, installing the development dependencies:

1$ npm install

then run the tests:

1$ npm test