@ripreact/logger

An opinionated logger for browser devtools.

Features:

• Configurable transports.
• debug-like namespaces.
• Logging with tags.
• Expressive severity levels.
• Convenient template-based API.
• Flexible and powerful filtering.
• Time differences for segments of namespace and tags.

Devtools transport features:

• Powerline formatting.
• Emoji code.

API

For advanced API docs see src/index.ts (after Internals region).

Logger

Creates new logger instance. Must be used without new keyword.

Severity levels

1. apocalypse — App owner should be alerted immediately. Emoji: Fuck!
2. fatal — App owner should be notified the next morning. Emoji: Rage.
3. crash — App owner may be notified depending on circumstances. Emoji: Angry.
4. error — App can recover on its own. Emoji: Shit.
5. warning — Nothing critical. Emoji: Shrug.
6. ok — Something good happened. Emoji: Ok.
7. log — Regular message in development. Emoji: Writing.
8. debug — Helps you to locate errors. Emoji: Paw.
9. flood — Use it to flood your console. Emoji: Eyes.

Namespace and tags

Marker  = _ (Segment (_ ':'+ _ Segment)*)? (_ '+'+ _ (Tag (_ ','+ _ Tag)*)?)? _

Segment = /[^:+,]/
Tag     = /[^:+,]/
_       = /\s*/

Message marker may include namespace and tags. Namespace includes names separated by :; tags include names separated by ,; + separates namespace and tags parts. Both segment and tag names may be surrounded by spaces; empty names will be ignored. You cannot use :, +, , in names.

Substitutions

@ripreact/logger doesn’t provide string formatting support by default; you may use transport, which supports it (e.g. devtools transport).

Usage

const logger = Logger({
    /**
     * Array of plugins.
     */
    plugins: [LevelFilter({ level: 'flood' }), DevtoolsTransport()],
});

// Levels:
logger.apocalypse`foo:bar`('App owner should be alerted immediately.');
logger.disaster`foo:bar`('App owner should be notified the next morning.');
logger.crash`foo:bar`('App owner may be notified depending on circumstances.');
logger.error`foo:bar`('App can recover on its own.');
logger.warning`foo:bar`('Nothing critical.');
logger.ok`foo:bar`('Something good happened.');
logger.log`foo:bar`('Regular message in development.');
logger.trace`foo:bar`('Helps you to locate errors.');
logger.flood`foo:bar`('Use it to flood your console.');

// Namespace and tags:
logger.log`company:product:package:class:method +tag1, tag2`('Foo bar.');

DevtoolsTransport

const logger = Logger({
    plugins: [
        DevtoolsTransport({
            /**
             * Transport-specific message preprocessor.
             */
            preprocessor: message => message,

            /**
             * Transport-specific filter. Applied before preprocessor.
             */
            filterMessages: () => true,

            /**
             * Segments filter; allows to hide specific segments (e.g company
             * name prefix).
             */
            filterSegments: ({ name }, index) => name != 'cyka' || index > 0,

            /**
             * Tags filter; allows to hide specific tags.
             */
            filterTags: ({ name }) => !/^user=\d+/.test(name),
        }),
    ],
});

LevelFilter

Filters messages by severity level.

const logger = Logger({
    plugins: [
        LevelFilter({
            /**
             * Most verbose allowed level. Defaults to `'warning'`.
             */
            level: 'debug',
        }),
    ],
});

PrefixPreprocessor

Prepends specific prefix (e.g. company/product/package name) to each namespace.

const logger = Logger({
    plugins: [
        PrefixPreprocessor({
            prefix: ['cyka', 'blyat'],
        }),
    ],
});

getMarker

Returns message marker string (normalized namespace and normalized deduped sorted tags).

const logger = Logger({
    plugins: [
        {
            preprocessor(message) {
                console.log(getMarker(message)); // ¯\_(ツ)_/¯
            },
        },
    ],
});

logger.log` : : a : : b : : + + , , c , , d , ,  +d, e`(); // `a:b +c,d`

logger

Default instance of logger. Provides default level filter and default transport.

Roadmap

• [ ] NodeJS console transport.
• [ ] HTTP transport.
• [ ] File transport.
• [ ] WebSocket transport.
• [ ] journald transport.
• [ ] Event Log transport.
• [ ] Stack traces.
• [ ] High resolution time.
• [ ] debug compatibility layer.
• [ ] Gotta Go Fast.