@holz/env-filter

Builds on @holz/pattern-filter to filter logs based on your current environment, loading the pattern from process.env.DEBUG or localStorage.debug.

Usage

import { createEnvironmentFilter } from '@holz/env-filter';
import { createLogger } from '@holz/core';

createLogger(
  createEnvironmentFilter({
    processor: plugin,
  })
);

Configuration Options

createEnvironmentFilter() accepts the following configuration options:

• processor: The log processor to use. Required.
• pattern: The pattern to use for filtering logs. If not provided, the pattern will be loaded from the environment.
• defaultPattern: The default pattern to use if no pattern is provided or detected in the environment. Default is '*' (all logs).
• localStorageKey: The name of the key used to store the pattern in localStorage. Default is 'debug'.
• environmentVariable: The name of the environment variable used to store the pattern. Default is 'DEBUG'.

Note that the pattern option will override any pattern detected in the environment.

How it Works

createEnvironmentFilter() loads the pattern from the environment using the following process:

• It looks for a pattern stored in localStorage with the key specified in localStorageKey. If found, it uses that pattern.
• If localStorage is not available or doesn't contain a pattern with the specified key, it looks for a pattern stored in process.env specified in environmentVariable. If found, it uses that pattern.
• If no pattern is found in either localStorage or the environment variable, it uses the default pattern specified in defaultPattern.

Once the pattern is loaded, createEnvironmentFilter() uses createPatternFilter() from @holz/pattern-filter to create a log processor that filters logs based on the loaded pattern.

Example

Suppose you want to filter logs in development that come from your app, but disable all logs in production. You can use @holz/env-filter to accomplish this by setting the DEBUG environment variable in development:

DEBUG=your-app*

In production, you may want to disable all logging by default. This can be done by setting the default pattern to an empty string:

import { createEnvironmentFilter } from '@holz/env-filter';
import { createLogger } from '@holz/core';

const logger = createLogger(
  createEnvironmentFilter({
    processor: yourProcessor,
    defaultPattern: '',
  })
);

With this configuration, logs will be disabled by default in production, and only logs originating from the your-app namespace will be shown in development.