SP.FieldCalculated.formula property (sp.js)
Gets or sets a value that specifies the formula for the field.
Applies to: apps for SharePoint | SharePoint Foundation 2013 | SharePoint Server 2013
var value = SP.FieldCalculated.get_formula ()
var value = SP.FieldCalculated.set_formula ()
Return value
Type: String
Remarks
It must not be empty.