Fixed serialization of NumPy dtype M values to milliseconds rather than nanoseconds.

Author: hcpchris

highcharts_core/options/series/data/cartesian.py

@@ -128,6 +128,8 @@ def x(self, value):
                 value = validators.datetime(value)
             elif checkers.is_date(value):
                 value = validators.date(value)
+            elif HAS_NUMPY and hasattr(value, 'dtype') and value.dtype.char == 'M':
+                value = (value.astype(np.int64) / 10**6).astype(np.int64)
             elif checkers.is_numeric(value):
                 value = validators.numeric(value)
             else:

highcharts_core/utility_functions.py

@@ -688,8 +688,10 @@ def from_ndarray(as_ndarray, force_enforced_null = False):
     else:
         nan_replacement = None
 
-    if as_ndarray.dtype.char not in ['O', 'U']:
+    if as_ndarray.dtype.char not in ['O', 'U', 'M']:
         stripped = np.where(np.isnan(as_ndarray), nan_replacement, as_ndarray)
+    elif as_ndarray.dtype.char == 'M':
+        stripped = (as_ndarray.astype(np.int64) / 10**6).astype(np.int64)
     else:
         prelim_stripped = as_ndarray.tolist()
         stripped = []