GAS: Having difficulty testing to see if activecell has a specific rangename - google-apps-script

Question

I have a source cell with the range name "source".
I have some target (non-adjacent) cells with the range names "target1", "target2", "target3".
If the cell "source" is changed, I want the value of it to be copied into the 3 target cells.
I'm stumbling at the first hurdle in that I cannot work out how to test if I'm editing the "source" cell.
All the documentation seems to be about naming ranges rather than then working with them.
So far I have...
function onEdit()
{
var sh = SpreadsheetApp.getActiveSheet();
var ss = SpreadsheetApp.getActiveSpreadsheet();
var range = ss.getActiveRange();
var C = range.getColumnIndex();
var a = sh.getActiveCell();
if( range == "LXbar1" )
{
SpreadsheetApp.getUi().alert('You are HERE!');
}
}
revised code:
function onEdit(e)
{
var ss = SpreadsheetApp.getActiveSpreadsheet();
// Active range
var eventRange = e.range;
// Active range address
var eventRangeA1 = eventRange.getSheet().getName() + "!" + eventRange.getA1Notation();
// Comparison range name
var sourceRange = ss.getRangeByName("rLXbar1");
// Comparison range address
var sourceRangeA1 = sourceRange.getSheet().getName() + "!" + sourceRange.getA1Notation();
if (eventRangeA1 === sourceRangeA1)
{
// Target range name
var targetRange = ss.getRangeByName("rLamp08");
targetRange.setValue(sourceRangeA1.value);
}
}

Answer 1

Don't use Active elements in onEdit triggers, use the built in event object it will ensure it will always use the actually selected cell when the edit happened.
function onEdit(e) {
var ss = SpreadsheetApp.getActiveSpreadsheet();
var eventRange = e.range;
var sourceRange = ss.getRangeByName("source");
var eventRangeA1 = eventRange.getSheet().getName() + "!" + eventRange.getA1Notation();
var sourceRangeA1 = sourceRange.getSheet().getName() + "!" + sourceRange.getA1Notation();
if (eventRangeA1 === sourceRangeA1) {
SpreadsheetApp.getUi().alert("You are HERE!");
}
};