logLevels :  ['debug', 'info', 'warn', 'error', 'fatal']

import VueLogger from 'vuejs-logger';
const isProduction = process.env.NODE_ENV === 'production';
 
const options = {
    isEnabled: true,
    logLevel : isProduction ? 'error' : 'debug',
    stringifyArguments : false,
    showLogLevel : true,
    showMethodName : true,
    separator: '|',
    showConsoleColors: true
};

Vue.use(VueLogger, options);

new Vue({
    data() {
        return {
            a : 'a',
            b : 'b'
        }
    },
    created() {
        this.$log.debug('test', this.a, 123)
        this.$log.info('test', this.b)
        this.$log.warn('test')
        this.$log.error('test')
        this.$log.fatal('test')
        externalFunction()
    }
});

function externalFunction() {
   // log from external function
   Vue.$log.debug('log from function outside component.');
}

    function foo() {
        // these statements will print nothing if the logLevel is set to 'fatal'. But they will compile just fine. 
        this.$log.debug('test', 'bar')
        this.$log.info('test')
        this.$log.warn('test')
        this.$log.error('test', 'foo')
        // this statement will print if the logLevel is set to 'fatal'
        this.$log.fatal('test', 'bar', 123)
    }