[Swift] Add documentation to input structs' init

Author: kevinmbeaulieu

packages/apollo-codegen-swift/src/__tests__/__snapshots__/codeGeneration.ts.snap

@@ -2011,6 +2011,10 @@ exports[`Swift code generation #typeDeclarationForGraphQLType() should generate
 public struct ReviewInput: GraphQLMapConvertible {
   public var graphQLMap: GraphQLMap
 
+  /// - Parameters:
+  ///   - stars: 0-5 stars
+  ///   - commentary: Comment about the movie, optional
+  ///   - favoriteColor: Favorite color, optional
   public init(stars: Int, commentary: Swift.Optional<String?> = nil, favoriteColor: Swift.Optional<ColorInput?> = nil) {
     graphQLMap = [\\"stars\\": stars, \\"commentary\\": commentary, \\"favorite_color\\": favoriteColor]
   }

packages/apollo-codegen-swift/src/codeGeneration.ts

@@ -1197,6 +1197,21 @@ export class SwiftAPIGenerator extends SwiftGenerator<CompilerContext> {
         this.printOnNewline(swift`public var graphQLMap: GraphQLMap`);
 
         this.printNewlineIfNeeded();
+
+        if (properties.length > 0) {
+          this.comment("- Parameters:");
+          properties.forEach(property => {
+            var propertyDescription = "";
+            if (property.description) {
+              propertyDescription = `: ${property.description}`;
+            }
+            this.comment(
+              `  - ${property.propertyName}${propertyDescription}`,
+              false
+            );
+          });
+        }
+
         this.printOnNewline(swift`public init`);
         this.print(swift`(`);
         this.print(

packages/apollo-codegen-swift/src/language.ts

@@ -388,10 +388,10 @@ export class SwiftGenerator<Context> extends CodeGenerator<
     }
   }
 
-  comment(comment?: string) {
+  comment(comment?: string, trim: Boolean = true) {
     comment &&
       comment.split("\n").forEach(line => {
-        this.printOnNewline(SwiftSource.raw`/// ${line.trim()}`);
+        this.printOnNewline(SwiftSource.raw`/// ${trim ? line.trim() : line}`);
       });
   }