ArcGIS JS uses GeoJSOLLayer, and its coordinate projection seems to only support SpatialReference.WGS84?
The following is the information I created with SpatialReference 3826, but it cannot be displayed on the layer.
{"type":"FeatureCollection","name":"TEST","features":[{"type":"Feature","properties":{"SeqNo":109},"geometry":{"type":"MultiPolygon","coordinates":[[[[179570.50600000005,2519531.6560000014],[179558.54800000042,2519680.1860000007],[179555.2360000005,2519725.4010000005],[179554.15799999982,2519740.119000001],[179553.0650000004,2519755.035],[179551.9570000004,2519770.153000001],[179550.8610000005,2519785.1110000014],[179549.5499999998,2519803.0080000013],[179548.0700000003,2519819.107000001],[179541.96100000013,2519897.33],[179541.40500000026,2519904.444],[179546.08100000024,2519903.432],[179549.9879999999,2519902.215],[179552.017,2519899.9189999998],[179558.03100000042,2519815.040000001],[179563.94100000057,2519734.16],[179595.41000000015,2519323.949000001],[179596.72900000028,2519306.756000001],[179603.02300000004,2519224.6850000005],[179609.15600000042,2519137.483000001],[179612.68500000052,2519094.091],[179605.7410000004,2519091.966],[179605.37179999985,2519097.6916000005],[179602.91700000037,2519135.7650000006],[179597.81000000052,2519199.473000001],[179596.0240000002,2519221.76],[179594.2910000002,2519244.188000001],[179590.70300000068,2519290.6050000004],[179589.1610000003,2519310.557],[179587.88599999994,2519327.046],[179579.07400000002,2519434.6670000013],[179577.85400000028,2519449.0500000007],[179576.46400000062,2519465.4690000005],[179575.02799999993,2519482.4280000012],[179571.7000000002,2519518.66],[179570.50600000005,2519531.6560000014]]]]}}]}
