[Solved]-How to access labels array using chart plugin (Chart.pluginService.register) in Chartjs 2.x?-Chart.js

Depending on your needs you can use the ticksoption to modify the labels. Do your checks of value and return based on your needs. docs

yAxes: [{
    ticks: {
        callback: function(value, index, values) {
            return value
        }
    }
}],

Just set the label and tooltip options like so

...
options: {
    legend: {
        display: false
    },
    tooltips: {
        callbacks: {
           label: function(tooltipItem) {
                  return tooltipItem.yLabel;
           }
        }
    }
}

Fiddle - http://jsfiddle.net/g19220r6/