v4.0.4

• fix merge object reference error. #79

v4.0.3

• fix umd url

v4.0.2

• fix export * error #78

v4.0.1

• optimize toDateString

v4.0.0

• support esm #IC67RZ

v3.9.1

• fix 76

v3.9.0

• support esm #67

v3.8.4

• update eqNull ts type.

v3.8.3

• fix toDateString 'options.firstDay' The issue of invalid default values.

v3.8.2

• Optimize toArrayTree、toTreeArray