test.js

async function adaptTable()
{
 var maxWidth = await getMaxWidth();
 var tableInfo = await getTableInfo();
 
 for (let row = 1; row <= tableInfo.rows ; row++) {
  
  var rowWidth = await getRowWidth(row, 
                                   tableInfo.cols,
                                   tableInfo.table); 
  
  var destinationWidth = rowWidth - maxWidth;  
  
  var tableCheck = await setRowWidth(row, 
                                     tableInfo.cols, 
                                     tableInfo.table, 
                                     destinationWidth, 
                                     rowWidth);
 };
 
 function getMaxWidth() {

  var maxWidth = 0;
  var pageWidth = 0;
  var marginLeft = 0;
  var marginRight = 0;

  return new Promise(resolve => {
  
   TXTextControl.setPageUnit(TXTextControl.MeasuringUnit.Twips, function() {
    TXTextControl.sections.getItem( function (section) {
     section.format.pageSize.getWidth(function (width) { 
      pageWidth = width;
      
      section.format.pageMargins.getLeft(function (left) { 
       marginLeft = left;
       
       section.format.pageMargins.getRight(function (right) { 
        marginRight = right;
        
        resolve(pageWidth - marginLeft - marginRight);
       });});});});});});
 }

 function getTableInfo() {

  var cols = 0;
  var rows = 0;
  
  return new Promise(resolve => {
  
   TXTextControl.tables.getItem( function (table) {
    
    if (table === null)
     return;
   
    table.rows.getCount(function(rowCount) {
     table.columns.getCount(function(colCount) {
     
      var tableInfo = {
       rows: rowCount,
       cols: colCount,
       table: table
      };
     
      resolve(tableInfo);
      
     });});});});
 }

 function getRowWidth(row, colCount, table) {

  
  return new Promise(resolve => {
   var currentWidth = 0;
         
   for (let col = 1; col <= colCount; col++) {
    
    table.cells.getItem(function (cell) {
     cell.getWidth(function (cellWidth) {
      currentWidth = currentWidth + cellWidth;
      
      if (col === colCount)
       resolve(currentWidth);
     });          
    }, null, row, col);};});

 }

 function setRowWidth(row, colCount, table, destinationWidth, currentWidth) {

  return new Promise(resolve => {    
   for (let col = 1; col <= colCount; col++) {
    
    // calculate the ratio percentage for each cell
    table.cells.getItem(function (cell) {
     cell.getWidth(function (cellWidth) {
      var percentage = cellWidth / currentWidth;
      
      cell.setWidth(parseInt(cellWidth - (destinationWidth * percentage)), function() {
       if (col === colCount)
        resolve(true);
      });
      
     });          
    }, null, row, col);};});}
 
}