var bx = require('barcode-js'); 
bx.analyze(params, function(err, results) {
/* ... */
});

// call bx.analyze to detect barcodes in the image
// all detected barcodes will be returned to the
// result object array.
var bx = require('barcode-js');
var params = {
    input: 'path/filename.ext',
    type: [ 'code128', 'code39']
}
bx.analyze(params, function(err, results) {
    if(err)
    {
        console.error("There was an error analyzing the barcode", err);
        return;
    }       
    else
    {
        results.forEach(function(item){
            console.log("area: x=%d, y=%d, width=%d, height=%d", item.area.x, item.area.y, item.area.width, item.area.height );
            console.log("type: %s", item.type);
            console.log("value: %s", item.value);
            console.log("corners: topLeftPoint(%d, %d), topRightPoint(%d, %d), bottomRightPoint(%d, %d), bottomLeftPoint(%d, %d)",
                item.corners[0].x, item.corners[0].y, item.corners[1].x, item.corners[1].y,item.corners[2].x, item.corners[2].y,item.corners[3].x, item.corners[3].y);
            console.log("confidence: %d", item.confidence);
        })  
    }
    
});