warn-once

Print a warning exactly once during development. Suitable for deprecation warnings, warnings for missing setup etc.

Installation

Open a Terminal in the project root and run:

npm install warn-once

The warnOnce function accepts a condition as the first argument. If the condition is true, then it'll print a warning:

const warnOnce = require('warn-once');

// ...

warnOnce(someCondition, 'This is a warning message');

You can call warnOnce multiple times, but if the warning was printed already, it'll not be printed again.

The warning is only shown during development, i.e. if NODE_ENV is not set to 'production'.