Handle parameter initializers

Author: michaldudak

src/parser.ts

@@ -427,19 +427,34 @@ export function parseFromProgram(
 
 		const checkedSignatures = type.getCallSignatures().map((signature) => {
 			return {
-				parameters: signature.parameters.map((param) => {
+				parameters: signature.parameters.map((parameterSymbol) => {
+					const parameterDeclaration = parameterSymbol.valueDeclaration as ts.ParameterDeclaration;
 					const type = checkType(
-						checker.getTypeOfSymbolAtLocation(param, param.valueDeclaration!),
+						checker.getTypeOfSymbolAtLocation(parameterSymbol, parameterDeclaration),
 						typeStack,
-						param.getName(),
+						parameterSymbol.getName(),
 					);
 
-					const parameterDescription = parameterDescriptions[param.getName()];
+					const documentation: t.Documentation = {};
+					documentation.description = parameterDescriptions[parameterSymbol.getName()];
+					const initializer = parameterDeclaration.initializer;
+					if (initializer) {
+						const initializerType = checker.getTypeAtLocation(initializer);
+						if (initializerType.flags & ts.TypeFlags.Literal) {
+							if (initializerType.isStringLiteral()) {
+								documentation.defaultValue = `"${initializer.getText()}"`;
+							} else {
+								documentation.defaultValue = initializer.getText();
+							}
+						}
+					}
+
+					const hasDocumentation = documentation.description || documentation.defaultValue;
 
 					return t.parameterNode(
 						type,
-						param.getName(),
-						parameterDescription ? { description: parameterDescription } : undefined,
+						parameterSymbol.getName(),
+						hasDocumentation ? documentation : undefined,
 					);
 				}),
 

test/hook-arrow-function/output.json

@@ -7,6 +7,7 @@
 			"parameters": [
 				{
 					"nodeType": "parameter",
+					"name": "parameters",
 					"type": {
 						"nodeType": "interface",
 						"members": [
@@ -38,11 +39,11 @@
 									"parameters": [
 										{
 											"nodeType": "parameter",
+											"name": "value",
 											"type": {
 												"nodeType": "intrinsic",
 												"type": "string"
-											},
-											"name": "value"
+											}
 										}
 									],
 									"returnValueType": {
@@ -54,8 +55,7 @@
 								"filenames": {}
 							}
 						]
-					},
-					"name": "parameters"
+					}
 				}
 			],
 			"returnValueType": {
@@ -69,11 +69,11 @@
 							"parameters": [
 								{
 									"nodeType": "parameter",
+									"name": "externalProps",
 									"type": {
 										"nodeType": "reference",
 										"typeName": "React.HTMLAttributes"
-									},
-									"name": "externalProps"
+									}
 								}
 							],
 							"returnValueType": {
@@ -90,4 +90,4 @@
 			"visibility": "internal"
 		}
 	]
-}
+}

test/hook-multiple-parameters/output.json

@@ -57,7 +57,8 @@
 						]
 					},
 					"documentation": {
-						"description": "The severity."
+						"description": "The severity.",
+						"defaultValue": "\"'low'\""
 					}
 				}
 			],
@@ -69,4 +70,4 @@
 			"visibility": "internal"
 		}
 	]
-}
+}