How to Create a Variable for Chart Js Datalabel Plugin Formatter

I am trying to write a global formatting variable for chart js datalabels plugin across all the charts I create. Here is my attempt -

Global Variable:

var datalabels_format_sanssymb = {
    function (value) {
        if (value >= 1000000000 || value <= -1000000000) {
            return (value / 1000000000).toFixed(1).replace(/\.0$/, '');
        }
        if (value >= 1000000 || value <= -1000000) {
            return (value / 1000000).toFixed(1).replace(/\.0$/, '');
        }
        if (value >= 1000 || value <= -1000) {
            return (value / 1000).toFixed(1).replace(/\.0$/, '');
        }
        return value;
    }
}

And here is where I want to call the variable in the chart javascript:

plugins: {
    datalabels: {
        formatter: datalabels_format_sanssymb,
        font: {
            size: 10,
            weight: 'bold'
        },
        color: '#333333'
    }
},

This doesn't seem to work. Am I doing this correctly?