Below is my onprepare & reporters. When I access result_path in reporters I got value as undefined.

onPrepare: function (config, capabilities) {
        today = new Date()
        date = today.getDate()
        time = date + "_" + today.getHours() + "hrs_" + today.getMinutes() + "mins_" + today.getSeconds() + "secs"
        result_path = './execution_time_'+ time
        
        if (!fs.existsSync(result_path)) {
            fs.mkdirSync(result_path);
        }
        
    },
    reporters: [['timeline', {
        outputDir: result_path+'/',
         fileName: 'timeliner-reporter.html',
         embedImages: true,
         images: {
             quality: 80,
             resize: false,
             reductionRation: 2
         },
         screenshotStrategy:'before:click'
     }]],