Emitted ReadonlyArrays as Dart Lists (dart-archive#53)

Author: derekxu16

lib/dart_libraries_for_browser_types.ts

@@ -954,6 +954,7 @@ const STDLIB_TYPE_REPLACEMENTS = new Map(Object.entries({
 
   'Date': 'DateTime',
   'Array': 'List',
+  'ReadonlyArray': 'List',
   'ArrayBuffer': 'ByteBuffer',
   // 'Promise': 'Future',    // TODO(jacobr): add back once we unify Promise and
   // Future.

lib/facade_converter.ts

@@ -321,6 +321,9 @@ export class FacadeConverter extends base.TranspilerBase {
       types: ReadonlyArray<ts.TypeNode>, options: TypeDisplayOptions, seperator?: string): string {
     seperator = seperator || ',';
     let that = this;
+    if (!types) {
+      return '';
+    }
     return types
         .map((type) => {
           return that.generateDartTypeName(type, addInsideTypeArgument(options));
@@ -416,6 +419,12 @@ export class FacadeConverter extends base.TranspilerBase {
           // Function may be used as a type but not in other cases
           name = 'Function';
           break;
+        case 'ReadonlyArray':
+          name =
+              this.generateDartName(node.typeName, setTypeArguments(options, node.typeArguments));
+          comment = 'ReadonlyArray<' +
+              this.generateTypeList(node.typeArguments, addInsideComment(options)) + '>';
+          break;
         case 'Partial':
           // Partial<X> is currently the same as X since all types are nullable in Dart
           name = this.generateDartTypeName(node.typeArguments[0]);

test/facade_converter_test.ts

@@ -173,6 +173,14 @@ abstract class DSVParsedArray<T> implements List<T> {
 }`);
   });
 
+
+  it('translates readonly array façades', () => {
+    expectWithTypes('declare const a : ReadonlyArray<number>;').to.equal(`@JS()
+external List<num> /*ReadonlyArray<num>*/ get a;`);
+    expectWithTypes('function f() : ReadonlyArray<string> {}').to.equal(`@JS()
+external List<String> /*ReadonlyArray<String>*/ f();`);
+  });
+
   describe('error detection', () => {
     it('supports imports', () => {
       expectWithTypes(`import {X} from "other";\nlet x:X;`).to.equal(`import "other.dart" show X;