SVY21 - EPSG:4757

WKT

GEOGCS["GCS_SVY21", 
	DATUM["D_SVY21", 
		SPHEROID["WGS_1984", 6378137.0, 298.257223563]], 
	PRIMEM["Greenwich", 0.0], 
	UNIT["Degree", 0.0174532925199433]]

WKT2

GEOGCRS["GCS_SVY21", 
	DATUM["D_SVY21", 
		ELLIPSOID["WGS_1984", 6378137.0, 298.257223563]], 
	PRIMEM["Greenwich", 0.0], 
	CS[ellipsoidal, 2], 
	AXIS["Latitude (lat)", north, 
		ORDER[1]], 
	AXIS["Longitude (lon)", east, 
		ORDER[2]], 
	ANGLEUNIT["Degree", 0.0174532925199433], 
	ID["EPSG", "4757"]]

Data from @esri/proj-codes

{
  "wkid": 4757,
  "latestWkid": 4757,
  "macro": "PE_GCS_SVY21",
  "name": "GCS_SVY21",
  "wkt": "GEOGCS[\"GCS_SVY21\",DATUM[\"D_SVY21\",SPHEROID[\"WGS_1984\",6378137.0,298.257223563]],PRIMEM[\"Greenwich\",0.0],UNIT[\"Degree\",0.0174532925199433]]",
  "wkt2": "GEOGCRS[\"GCS_SVY21\",DATUM[\"D_SVY21\",ELLIPSOID[\"WGS_1984\",6378137.0,298.257223563]],PRIMEM[\"Greenwich\",0.0],CS[ellipsoidal,2],AXIS[\"Latitude (lat)\",north,ORDER[1]],AXIS[\"Longitude (lon)\",east,ORDER[2]],ANGLEUNIT[\"Degree\",0.0174532925199433],ID[\"EPSG\",\"4757\"]]",
  "description": "SVY21",
  "authority": "EPSG",
  "version": "9.5.5(9.3.0.0)",
  "deprecated": "no",
  "areaname": "Singapore",
  "extent": {
    "slat": 1.13,
    "nlat": 1.47,
    "llon": 103.59,
    "rlon": 104.07
  }
}