fabric.js set text

html

 <canvas id="c" width="400" height="200"></canvas>

js

var canvas = new fabric.Canvas('c');

var Bar = new fabric.Text('Bar', {selectable: false, top: 50, left: 10});


var rect = new fabric.Rect({width: 100, height: 100, left: 100, top: 100, fill: 'red'});
var group = new fabric.Group([rect, Bar], {selectable: true, top: 50, left: 100});
canvas.add(group);

canvas.renderAll();

Bar.setText("my_text");
canvas.renderAll();

or

$(document).click(function(e) {
    Bar.setText('selected');
});