JSFiddle - React, Tailwind, and code Playground
HTML
<input type="text" id="txt1" value="[16,57.35], [23,56.26], [34,54.57]" />
JavaScript
data = $('#txt1').val();
arr = JSON.parse ("["+data+"]");
console.log(arr);
<input type="text" id="txt1" value="[16,57.35], [23,56.26], [34,54.57]" />
data = $('#txt1').val();
arr = JSON.parse ("["+data+"]");
console.log(arr);