Super-simple invariant function

Usage

What is this package?

It's the simplest possible invariant/assert function. The code is:

function invariant( condition, message ) {
  if ( !condition ) {
    throw new Error( message || 'Invariant failed' );
  }
};

So, this code:

if ( !foo ) throw new Error( 'foo must be truthy' );

...can be replaced with the shorter:

invariant( foo, 'foo must be truthy' );

Isn't this the same as tiny-invariant?

Pretty much. The only difference is that the error thrown will always have the full error message, regardless of whether process.env.NODE_ENV === 'production' or not.

Versioning

This module follows semver. Breaking changes will only be made in major version updates.

All active NodeJS release lines are supported (v10+ at time of writing). After a release line of NodeJS reaches end of life according to Node's LTS schedule, support for that version of Node may be dropped at any time, and this will not be considered a breaking change. Dropping support for a Node version will be made in a minor version update (e.g. 1.2.0 to 1.3.0). If you are using a Node version which is approaching end of life, pin your dependency of this module to patch updates only using tilde (~) e.g. ~1.2.3 to avoid breakages.

Tests

Use npm test to run the tests. Use npm run cover to check coverage.

Changelog

See changelog.md

Issues

If you discover a bug, please raise an issue on Github. https://github.com/overlookmotel/simple-invariant/issues

Contribution

Pull requests are very welcome. Please:

• ensure all tests pass before submitting PR
• add tests for new features
• document new functionality/API additions in README
• do not add an entry to Changelog (Changelog is created when cutting releases)