Merge pull request #77 from atsu85/issue-76-javaType-to-TS-Declare-Type

feat(typeMapping): fix #76 - allow adding type mapping from java clas…

Author: atsu85

java2typescript-jackson/README.md

@@ -131,3 +131,23 @@ new Configuration().addType(CustomDate.class, DateType.getInstance())
 
 where `DateType` class specifies the expected output type name.
 
+
+##### Emitting `declare type SomeTypeName = SomeOtherTypeOrTypeExpression` instead of interface
+There are cases where instead of asking to emit TypeScript interface for specific Java type,
+You might want to specify the TypeScript type declaration
+(with potentially different type name)
+to be used instead of the interface of the Java type. Here is an example:
+
+You might have `LocalDate` class in Java, and custom deserializer that can accept either string or number, so that in TypeScript You should be able to assign either of them to that type:
+```TypeScript
+type DateWithoutTime = string | number;
+```
+This could be accomplished using custom configuration:
+```Java
+Configuration conf = new Configuration()
+	.addType(LocalDate.class, new TypeDeclarationType("DateWithoutTime", "string | number"));
+```
+There are more use-cases for this solution - see
+[the description of the issue](https://github.com/raphaeljolivet/java2typescript/issues/76)
+and the test [source](src/test/java/java2typescript/jackson/module/CustomTypeDefinitionGeneratorTest.java#L82)
+and [output](src/test/resources/java2typescript/jackson/module/CustomTypeDefinitionGeneratorTest.classWithCustomTypeFields.d.ts) as an example.

java2typescript-jackson/src/main/java/java2typescript/jackson/module/DefinitionGenerator.java

@@ -16,11 +16,16 @@
 package java2typescript.jackson.module;
 
 import java.util.Collection;
-import java2typescript.jackson.module.grammar.Module;
-import java2typescript.jackson.module.visitors.TSJsonFormatVisitorWrapper;
 
+import com.fasterxml.jackson.databind.JavaType;
 import com.fasterxml.jackson.databind.JsonMappingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.type.SimpleType;
+
+import java2typescript.jackson.module.grammar.Module;
+import java2typescript.jackson.module.grammar.TypeDeclarationType;
+import java2typescript.jackson.module.grammar.base.AbstractType;
+import java2typescript.jackson.module.visitors.TSJsonFormatVisitorWrapper;
 
 /**
  * Main class that generates a TypeScript grammar tree (a Module), out of a
@@ -51,6 +56,15 @@ public Module generateTypeScript(String moduleName, Collection<? extends Class<?
 		TSJsonFormatVisitorWrapper visitor = new TSJsonFormatVisitorWrapper(module, conf);
 
 		for (Class<?> clazz : classes) {
+			AbstractType customType = conf.getCustomTypes().get(clazz.getName());
+			if(customType != null && customType instanceof TypeDeclarationType) {
+				// When the class is registered as TypeDeclarationType, then ...
+				String tsTypeName = conf.getNamingStrategy().getName(SimpleType.construct(clazz));
+				// ... add that type to the module ...
+				module.getNamedTypes().put(tsTypeName, (TypeDeclarationType)customType);
+				// ... instead of inspecting class body
+				continue;
+			}
 			mapper.acceptJsonFormatVisitor(clazz, visitor);
 		}
 		return module;

java2typescript-jackson/src/main/java/java2typescript/jackson/module/grammar/TypeDeclarationType.java

@@ -0,0 +1,38 @@
+package java2typescript.jackson.module.grammar;
+
+import static java.lang.String.format;
+
+import java.io.IOException;
+import java.io.Writer;
+
+import java2typescript.jackson.module.grammar.base.AbstractNamedType;
+import java2typescript.jackson.module.writer.WriterPreferences;
+
+/**
+ * {@link java2typescript.jackson.module.grammar.base.AbstractType} that has name, like classes/interfaces,
+ * but instead of body the type has declared value.
+ * <p>
+ * For example
+ * `type NumberOrString = number | string`
+ * that can be expressed with
+ * <p>
+ * `new TypeDeclarationType("NumberOrString", "number | string")`
+ *
+ * @author Ats Uiboupin
+ */
+public class TypeDeclarationType extends AbstractNamedType {
+
+	private String typeScriptType;
+
+	public TypeDeclarationType(String className, String typeScriptType) {
+		super(className);
+		this.typeScriptType = typeScriptType;
+	}
+
+	@Override
+	public void writeDefInternal(Writer writer, WriterPreferences preferences) throws IOException {
+		// TODO separate writer for this type
+		writer.write(format("type %s = %s;", name, typeScriptType));
+	}
+
+}

java2typescript-jackson/src/main/java/java2typescript/jackson/module/visitors/TSJsonObjectFormatVisitor.java

@@ -27,6 +27,7 @@
 import java2typescript.jackson.module.grammar.AnyType;
 import java2typescript.jackson.module.grammar.FunctionType;
 import java2typescript.jackson.module.grammar.ClassType;
+import java2typescript.jackson.module.grammar.TypeDeclarationType;
 import java2typescript.jackson.module.grammar.VoidType;
 import java2typescript.jackson.module.grammar.base.AbstractType;
 
@@ -161,6 +162,10 @@ protected AbstractType getTSTypeForProperty(BeanProperty writer) throws JsonMapp
 
 		AbstractType customType = conf.getCustomTypes().get(type.getRawClass().getName());
 		if(customType != null) {
+			if(customType instanceof TypeDeclarationType) {
+				TypeDeclarationType tdt = (TypeDeclarationType) customType;
+				getModule().getNamedTypes().put(tdt.getName(), tdt);
+			}
 			return customType;
 		}
 

java2typescript-jackson/src/test/java/java2typescript/jackson/module/CustomTypeDefinitionGeneratorTest.java

@@ -19,10 +19,12 @@
 import java.io.IOException;
 import java.io.StringWriter;
 import java.io.Writer;
+import java.util.Date;
 
 import org.junit.Test;
 
 import java2typescript.jackson.module.grammar.Module;
+import java2typescript.jackson.module.grammar.TypeDeclarationType;
 import java2typescript.jackson.module.grammar.base.AbstractPrimitiveType;
 import java2typescript.jackson.module.util.ExpectedOutputChecker;
 import java2typescript.jackson.module.util.TestUtil;
@@ -36,6 +38,15 @@ class TestClass {
 	}
 
 	public class CustomDate {
+		public Date value;
+	}
+
+	public class LongValueAddedDirectlyToModule {
+		public Long value;
+	}
+
+	public class Unused {
+		public Long value;
 	}
 
 	public static class DateType extends AbstractPrimitiveType {
@@ -66,4 +77,25 @@ public void classWithCustomTypeFields() throws IOException {
 		// Assert
 		ExpectedOutputChecker.checkOutputFromFile(out);
 	}
+
+	@Test
+	public void declareTypeInsteadOfEmittingInterface() throws IOException {
+		// Arrange
+		Configuration conf = new Configuration()
+				.addType(CustomDate.class, new TypeDeclarationType("DateStringOrNumber", "string | number"))
+				.addType(LongValueAddedDirectlyToModule.class, new TypeDeclarationType("NumericValue", "number"))
+				.addType(Unused.class, new TypeDeclarationType("Unused", "shouldNotBeEmitted"));
+		Module module = TestUtil.createTestModule(conf, TestClass.class, LongValueAddedDirectlyToModule.class);
+		Writer out = new StringWriter();
+
+		// Act
+		new ExternalModuleFormatWriter().write(module, out);
+		out.close();
+		System.out.println(out);
+
+		// Assert
+		ExpectedOutputChecker.checkOutputFromFile(out);
+	}
+
+
 }

java2typescript-jackson/src/test/resources/java2typescript/jackson/module/CustomTypeDefinitionGeneratorTest.declareTypeInsteadOfEmittingInterface.d.ts

@@ -0,0 +1,8 @@
+export interface TestClass {
+    customDate: DateStringOrNumber;
+    customDateArray: DateStringOrNumber[];
+}
+
+export type DateStringOrNumber = string | number;
+
+export type NumericValue = number;