yurnalist
v2.1.0
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Elegant console output, borrowed from Yarn
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Yurnalist
An elegant console reporter, borrowed from Yarn.
Introduction
Pretty console output makes developers happy and Yarn is doing a nice job. Yurnalist takes the internal console reporter code from Yarn and makes it available for use in other Node.js applications.
The current version is based on code from Yarn v1.13.0.
Yurnalist can be used to report many different things besides simple messages.
Features
- log, info, warn, succes, error & command messages
- progress bars
- activity spinners
- process steps
- object inspection
- lists
- emojis
- trees
- tables
- user question
- user select
- program header & footer
Install
yarn add yurnalist
Or if your prefer NPM
npm install yurnalist
How to use
Here is an example showing a combination of different reporter API functions.
import report from 'yurnalist'
/* A function to fake some async task */
function waitNumberOfSecs(secs) {
return new Promise((resolve) => setTimeout(resolve, secs * 1000));
}
async function fetchSomething() {
report.info('Please wait while I fetch something for you.');
report.warn('It might take a little while though.');
const spinner = report.activity();
spinner.tick('I am on it!');
try {
await waitNumberOfSecs(1);
spinner.tick('Still busy...');
await waitNumberOfSecs(1);
spinner.tick('Almost there...');
await waitNumberOfSecs(1);
report.success('Done!');
} catch (err) {
report.error(err);
}
spinner.end();
}
fetchSomething();
Requirements
Node >= 4
Examples
Examples showing different API functions are found in /examples.
You can run them directly with node >= 7.6 (because of async/await syntax). For
older versions you could use the --harmony
flag, or otherwise Babel.
To run the activity example:
node examples/activity.js
Configuration
A normal import gives you a reporter instance configured with defaults for easy
use. If you want something else you can call createReporter(options)
to give
you an instance with different options.
Options
These are the options of the reporter as defined by Flow:
type ReporterOptions = {
verbose?: boolean,
stdout?: Stdout,
stderr?: Stdout,
stdin?: Stdin,
emoji?: boolean,
noProgress?: boolean,
silent?: boolean,
nonInteractive?: boolean,
peekMemoryCounter?: boolean
};
The defaults used are:
const defaults = {
verbose: false,
stdout: process.stdout,
stderr: process.stderr,
stdin: process.stdin,
emoji: true,
noProgress: false,
silent: false,
nonInteractive: false,
peekMemoryCounter: false
}
The peekMemoryCounter is disabled by default. If you enable it, you'll have to
call reporter.close()
to stop its running timer. Otherwise your program will
not exit. The memory counter can be used to display in the footer data.
Silent Mode and CI
Silent mode can be set via the options passed to createReporter. It disables
output for various functions like info
, list
, activity
and progress
. The
output from warning
and error
messages is not silenced.
Silent mode can also be enabled with the YURNALIST_SILENT
environment
variable.
In CI environments the output from activity
and progress
is disabled.
API
The API still needs some documentation, but most methods are straightforward. In the meantime you can also look at the examples and possibly even the tests.
The following functions are available:
table
step
inspect( thing: mixed )
Pretty-prints the thing
.
list(title: string, items: Array, hints?: Object)
Generates a list of the provided items. Turns into a definition list if hints
are provided.
Example of a simple list:
report.list('My grocery list', ['bananas', 'tulips', 'eggs', 'bamischijf']);
Outputs:
list My grocery list
- bananas
- tulips
- eggs
- bamischijf
Example with hints:
const items = ['bananas', 'tulips', 'eggs', 'bamischijf'];
const hints = {
bananas: 'for baking',
tulips: 'because it makes you happy',
eggs: 'not the cheap ones though',
bamischijf: 'if they have it',
};
report.list('My grocery list', items, hints);
Outputs:
list My grocery list
- bananas
for baking
- tulips
because it makes you happy
- eggs
not the cheap ones though
- bamischijf
if they have it
header
footer
log
success
error
info
command
warn
question
tree
activitySet
activity
select
progress
close
createReporter
Language
Yarn uses a language file for certain messages. For example if you try to skip a required question, or when you pick an invalid item from a select. This language file is not yet exposed in the Yurnalist API. The only supported language is English, as it is in Yarn at the moment.
I plan to make this configurable so that you can define your own messages in your own language .
Emojis
You can use Emojis in your output. Yurnalist should disable them if they are not allowed in the application environment.
Check:
Credits
Of course ❤️ and credits to all the contributers of Yarn. The ease with which I was able to extract this module from their codebase is proving some awesome engineering skills.