test-engine

Demand a Node or npm version to run your app.

Why?

• Fail fast with a friendly message.
• Get semver satisfaction between the expected and actual versions.
• Provide expected versions at runtime or via package.json.
• Provide actual versions at runtime, if you know them already.

Install

npm install test-engine --save

Usage

Get it into your program.

const testEngine = require('test-engine');

Ask whether the current Node and/or npm in use are acceptable based on the engines in your package.json.

testEngine().then((satisfied) => {
    if (!satisfied) {
        console.error('Hey Jane! Update your Node.');
    }
});

If you want to override the expectations of your package.json, you can.

testEngine({ npm : '2.x' }).then((satisfied) => {
    // true if on any version of npm 2
    console.log(satisfied);
});

If you happen to know the user's engines, you may provide them. This is particularly good for npm, because its version must be determined via the filesystem.

testEngine({ npm : '2.x' }, { npm : '3.0.0' })
    .then((satisfied) => {
        console.log(satisfied);  // => false
    });

Ask for a more detailed report.

testEngine(null, null, { detail : true })
    .then((engines) => {
        console.log(engines);
        // {
        //     allSatisfied : false,
        //     satisfied : {
        //         npm : {
        //             expected : '^2.0.0',
        //             actual   : '2.14.2'
        //         }
        //     },
        //     notSatisfied : {
        //         node : {
        //             expected : '>4.2.0',
        //             actual   : '4.0.0'
        //         }
        //     }
        // }
    });

You can register a handler that will only run when the user has compatible engines. If they do not match according to semver, the promise will be rejected.

testEngine.assert().then(() => {
    // Do anything. User is gauranteed to have compatible engines.
    console.log('Hey Jane! You are good to go.');
});

Contributing

See our contributing guidelines for more details.

1. Fork it.
2. Make a feature branch: git checkout -b my-new-feature
3. Commit your changes: git commit -am 'Add some feature'
4. Push to the branch: git push origin my-new-feature
5. Submit a pull request.

License

MPL-2.0 © Seth Holladay

Go make something, dang it.