GEE - Filter by list of partial PRODUCT_ID properties

Question

I got a list of partial PRODUCT_IDS, like:

var partials = ['S2B_MSIL2A_20210807T075609', 'S2B_MSIL2A_20210827T075609']

How do I filter a collection with that list?

There are 2 functions:

var s2_sr_col = ee.ImageCollection('COPERNICUS/S2_SR_HARMONIZED')
    .filterBounds(g)
    .filter(ee.Filter.inList('PRODUCT_ID', IMG_LIST))

-- this one only filters by full PRODUCT_ID strings

and:

var s2_sr_col = ee.ImageCollection('COPERNICUS/S2_SR_HARMONIZED')
        .filterBounds(g)
        .filter(ee.Filter.stringContains('PRODUCT_ID', partial_id))

--- this only filters by one partial id

How do I merge the both together so it would filter by list of partial names?

When I do something like this:

var s2_sr_coln = ee.ImageCollection('COPERNICUS/S2_SR_HARMONIZED')
.filterBounds(g)
var final_col = s2_sr_coln.filter(ee.Filter.stringContains('PRODUCT_ID', IMG_LIST[0]))
for(var i=1; i < IMG_LIST.length; i++){
  final_col = final_col.merge(s2_sr_coln.filter(ee.Filter.stringContains('PRODUCT_ID', IMG_LIST[i])));
}

it seems to work, but... the problem is that it changes system:index on every merge. And I need original indexes.

Output indexes are something like this (it adds something before them on every merge):

0: 1_1_1_1_1_1_1_1_1_1_1_1_20210807T075609_20210807T081506_T36MTB
1: 1_1_1_1_1_1_1_1_1_1_1_2_20210827T075609_20210827T081448_T36MTB
2: 1_1_1_1_1_1_1_1_1_1_2_20210921T075621_20210921T080228_T36MTB
3: 1_1_1_1_1_1_1_1_1_1_2_20210921T075621_20210921T082107_T36MTB
4: 1_1_1_1_1_1_1_1_1_2_20211220T080341_20211220T080337_T36MTB
5: 1_1_1_1_1_1_1_1_2_20220129T080201_20220129T081736_T36MTB
6: 1_1_1_1_1_1_1_2_20220129T080201_20220129T081736_T36MTB
7: 1_1_1_1_1_1_2_20220208T080101_20220208T081919_T36MTB
8: 1_1_1_1_1_2_20220409T075611_20220409T082104_T36MTB
9: 1_1_1_1_2_20220519T075621_20220519T082029_T36MTB
10: 1_1_1_2_20220618T075621_20220618T081516_T36MTB
11: 1_1_2_20220628T075621_20220628T081518_T36MTB
12: 1_2_20220708T075621_20220708T081518_T36MTB
13: 2_20220728T075621_20220728T081514_T36MTB

Should be:

0: 20210807T075609_20210807T081506_T36MTB
1: 20210827T075609_20210827T081448_T36MTB
2: 20210921T075621_20210921T080228_T36MTB
3: 20210921T075621_20210921T082107_T36MTB
4: 20211220T080341_20211220T080337_T36MTB
5: 20220129T080201_20220129T081736_T36MTB
6: 20220129T080201_20220129T081736_T36MTB
7: 20220208T080101_20220208T081919_T36MTB
8: 20220409T075611_20220409T082104_T36MTB
9: 20220519T075621_20220519T082029_T36MTB
10: 20220618T075621_20220618T081516_T36MTB
11: 20220628T075621_20220628T081518_T36MTB
12: 20220708T075621_20220708T081518_T36MTB
13: 20220728T075621_20220728T081514_T36MTB

Answer 1

You should't use for loops with Earth Engine, and you definitely shouldn't merge() a bunch of times. Instead, build a collection of collections and flatten() the result.

var s2 = ee.ImageCollection('COPERNICUS/S2_SR_HARMONIZED').filterBounds(geometry)
var partials = ['S2B_MSIL2A_20210807T075609', 'S2B_MSIL2A_20210827T075609']
var result = partials.map(function(str) {
  return s2.filter(ee.Filter.stringContains('PRODUCT_ID', str))
})
result = ee.FeatureCollection(result).flatten()
result = ee.ImageCollection(result)

Beware,

1. stringContains and stringStartsWith are both really expensive, because it can't use the index.
2. The filter might return more than one result.