How can I get a voluntary text fragment within start and end index - fabricjs

Question

I need to get text within start and end index.
For example for a text like
"Fabric.js is a powerful and simple Javascript HTML5 canvas library"
for start index "0" and end index "8" it must show the result "Fabric.js".
Is there a method similar to getSelectedText(start, end)?
With the difference that I need to get a voluntary text fragment, not the selected one

Answer 1

Your question is kinda vague. I am not sure I understand what you mean by 'voluntary text fragment'.
However, if you are using a fabric.IText instance, you can use the following attributes to get/set the start & end of the text selection :
var canvas = this.__canvas = new fabric.Canvas('Canvas');
var myText = new fabric.IText('Fabric.js is a powerful and simple Javascript HTML5 canvas library',{
top: 50,
left: 50,
fontSize: 20
});
canvas.add(myText);
canvas.renderAll();
myText.enterEditing(); // Enter text editing mode
myText.selectionStart = 0;
myText.selectionEnd = 9;
<script src="https://cdnjs.cloudflare.com/ajax/libs/fabric.js/4.3.1/fabric.js"
integrity="sha512-CzyxOXSECwo2nGJQZ2P8fdDxWVMVzn0jNdT2lYJ3afbqDJbaQ4qxgv9sLc85f6KP8HO2y929Bu+lnPKGC3ofSg=="
crossorigin="anonymous"></script>
<div class="container">
<canvas id="Canvas" width="700" height="300"></canvas>
</div>
<script src="canvas.js"></script>