How can I change the Data format in xProperties of GEE Chart?

Question

My goal is export CSV table with 2 columns: system:time_start in format YYYYMMddHHmmss and LST_median. For this I try to create Chart first but xProperty wants just a string like system:time_start and not a function which change a format of the data. How can I solve this problem and have my CSV table?

var chart = ui.Chart.image.series({
imageCollection: scaledReducedl8.select('ST_B10').filterDate('2021-01-01', '2021-12-31'),
region: geometry.buffer(17),
reducer: ee.Reducer.median(),
xProperty: ee.Date('system:time_start').format('YYYYMMddHHmmss')
}).setSeriesNames(['LST_median']);

print('median LST with revisit time data', chart);

Answer 1

You can map over the collection and add a property with the formatted date. Use that property as xProperty when charting.

var scaledReducedl8 = ee.ImageCollection('LANDSAT/LC08/C02/T1_L2')
  .filterBounds(geometry)
  .filterDate('2021-01-01', '2022-01-01') // End date is exclusive
  .select('ST_B10')
  .map(function (image) {
    return image.set('formattedDate', image.date().format('YYYYMMddHHmmss'))
  })

var chart = ui.Chart.image.series({
  imageCollection: scaledReducedl8,
  region: geometry.buffer(17),
  reducer: ee.Reducer.median(),
  xProperty: 'formattedDate'
}).setSeriesNames(['LST_median']);

print(chart)

https://code.earthengine.google.com/0bbff9acefc6a80f6ba8b7119a30eb0c