How to set the value of columns of current row of table from JavaScript.

Summary

How to set the value of columns of current row of table from JavaScript.

Content

My requirement is to have empty table on screen with ability to input text in few columns. on value change of first column an action change is defined that calls a rest service and returns records that are displayed in a popup. Based on selected record from popup few fields of the table needs to be set. I am trying to achieve this by calling a JS function from action chain. But I am unable to get access of the current row of the table.