JavaScript Code

Writing

Excel.run(function (context) { 
                context.workbook.worksheets.getActiveWorksheet().getRange("A1:C3").formulas = "=RAND()*17"; 
    return context.sync(); 
}).catch(function (error) { 
   console.log(error); 
}); 

Excel.run(function (context) { 
   var range = context.workbook.worksheets.getItem("Sheet1").getRange("A1:B2"); 
   range.formulas = [["=RAND()*12", "=RAND()*19"], ["=A1*.7", "=B1*.9"]]; 
   return context.sync();             
}).catch(function (error) { 
   console.log(error); 
}); 

Reading

Excel.run(function (context) { 
    var range = context.workbook.worksheets.getActiveWorksheet().getRange("A1:C3").load("formulas"); 
     return context.sync().then(function() { 
      for (var i = 0; i < range.formulas.length; i++) { 
          for (var j = 0; j < range.formulas[i].length; j++) { 
              console.log(range.formulas[i][j]); 
          } 
      } 
   console.log("done");      
   }); 
}).catch(function (error) { 
   console.log(error); 
}); 

Read calculation mode

Excel.run(function (context) { 
   var application = context.workbook.application.load("calculationMode"); 
   return context.sync().then(function () { 
      console.log(application.calculationMode);                                           
   });           
}).catch(function (error) { 
   console.log(error); 
}); 

Calculate workbooks

Excel.run(function (context) { 
   context.workbook.application.calculate(Excel.CalculationType.full); 
   return context.sync();             
}).catch(function (error) { 
   console.log(error); 
});