function checkSubscriptionArgument()

in src/common/channel.js [138:145]

• 8 lines of code
• 3 McCabe index (conditional complexity)

function checkSubscriptionArgument (argument) {
    if (typeof argument !== 'function' && typeof argument.handleEvent !== 'function') {
        throw new Error(
            'Must provide a function or an EventListener object ' +
                'implementing the handleEvent interface.'
        );
    }
}