Use import type for the typescript abstraction library code where relevant

CHANGELOG.md

@@ -11,7 +11,6 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Added the title of the API in the VSCode tree view. [#2779](https://github.com/microsoft/kiota/issues/2779)
 - Added capability to serialize and deserialize UUIDs in typescript[#40](https://github.com/microsoft/kiota-typescript/issues/40)
-- Use `import type` statement if the generated code is an interface[#2959](https://github.com/microsoft/kiota/issues/2959)
 - Added auto-generation header for class and enums in CSharp [#2886](https://github.com/microsoft/kiota/issues/2886)
 - Added support for multipart form data request body in CSharp, Go, Java, and TypeScript. [#220](https://github.com/microsoft/kiota/issues/220)
 - Added support for base64 encoded properties in TypeScript.
@@ -28,6 +27,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Added `Method` to the list of `CSharpReservedClassNames`. [#2939](https://github.com/microsoft/kiota/pull/2939)
 - Changed generation to use aggregate type for `TimeSpan` values in java [#2069](https://github.com/microsoft/kiota/issues/2069)
 - Fixed generation of properties with identical names after symbol cleanup. [#2869](https://github.com/microsoft/kiota/issues/2869)
+- Use `import type` syntax in Typescript for all code that will be arrased from output at runtime[#2959](https://github.com/microsoft/kiota/issues/2959)
 
 ## [1.4.0] - 2023-07-07
 

src/Kiota.Builder/CodeDOM/CodeUsing.cs

@@ -16,6 +16,10 @@ public bool IsExternal
     {
         get => Declaration?.IsExternal ?? true;
     }
+    public bool IsErasable
+    {
+        get; set;
+    }
     public string Alias { get; set; } = string.Empty;
     public object Clone()
     {
@@ -25,6 +29,7 @@ public object Clone()
             Alias = Alias,
             Name = Name,
             Parent = Parent,
+            IsErasable = IsErasable,
         };
     }
 }

src/Kiota.Builder/Refiners/AdditionalUsingEvaluator.cs

@@ -1,9 +1,11 @@
 using System;
-
 using Kiota.Builder.CodeDOM;
 
 namespace Kiota.Builder.Refiners;
 
 #pragma warning disable CA1819
-public record AdditionalUsingEvaluator(Func<CodeElement, bool> CodeElementEvaluator, string NamespaceName, params string[] ImportSymbols);
+public record AdditionalUsingEvaluator(Func<CodeElement, bool> CodeElementEvaluator, string NamespaceName, bool IsErasable = false, params string[] ImportSymbols)
+{
+    public AdditionalUsingEvaluator(Func<CodeElement, bool> CodeElementEvaluator, string NamespaceName, params string[] ImportSymbols) : this(CodeElementEvaluator, NamespaceName, false, ImportSymbols) { }
+}
 #pragma warning restore CA1819

src/Kiota.Builder/Refiners/CommonLanguageRefiner.cs

@@ -480,6 +480,7 @@ private static IEnumerable<CodeUsing> usingSelector(AdditionalUsingEvaluator x)
         {
             Name = y,
             Declaration = new CodeType { Name = x.NamespaceName, IsExternal = true },
+            IsErasable = x.IsErasable,
         });
     protected static void AddDefaultImports(CodeElement current, IEnumerable<AdditionalUsingEvaluator> evaluators)
     {

src/Kiota.Builder/Refiners/TypeScriptRefiner.cs

@@ -192,31 +192,48 @@ currentInterface.StartBlock is InterfaceDeclaration interfaceDeclaration &&
     }
     private const string GuidPackageName = "guid-typescript";
     private const string AbstractionsPackageName = "@microsoft/kiota-abstractions";
+    // A helper method to check if a parameter is a multipart body
+    private static bool IsMultipartBody(CodeParameter p) =>
+        p.IsOfKind(CodeParameterKind.RequestBody) &&
+        p.Type.Name.Equals(MultipartBodyClassName, StringComparison.OrdinalIgnoreCase);
+
+    // A helper method to check if a method has a multipart body parameter
+    private static bool HasMultipartBody(CodeMethod m) =>
+        m.IsOfKind(CodeMethodKind.RequestExecutor, CodeMethodKind.RequestGenerator) &&
+        m.Parameters.Any(IsMultipartBody);
+    // for Kiota abstration library if the code is not required for runtime purposes e.g. interfaces then the IsErassable flag is set to true
     private static readonly AdditionalUsingEvaluator[] defaultUsingEvaluators = {
         new (x => x is CodeProperty prop && prop.IsOfKind(CodePropertyKind.RequestAdapter),
-            AbstractionsPackageName, "RequestAdapter"),
+            AbstractionsPackageName, true, "RequestAdapter"),
         new (x => x is CodeProperty prop && prop.IsOfKind(CodePropertyKind.Options),
-            AbstractionsPackageName, "RequestOption"),
+            AbstractionsPackageName, true, "RequestOption"),
         new (x => x is CodeMethod method && method.IsOfKind(CodeMethodKind.RequestGenerator),
-            AbstractionsPackageName, "HttpMethod", "RequestInformation", "RequestOption"),
+            AbstractionsPackageName, false, "HttpMethod", "RequestInformation"),
+        new (x => x is CodeMethod method && method.IsOfKind(CodeMethodKind.RequestGenerator),
+            AbstractionsPackageName, true, "RequestOption"),
         new (x => x is CodeMethod method && method.IsOfKind(CodeMethodKind.Serializer),
-            AbstractionsPackageName, "SerializationWriter"),
+            AbstractionsPackageName, true,"SerializationWriter"),
         new (x => x is CodeMethod method && method.IsOfKind(CodeMethodKind.Deserializer, CodeMethodKind.Factory),
-            AbstractionsPackageName, "ParseNode"),
+            AbstractionsPackageName, true, "ParseNode"),
         new (x => x is CodeMethod method && method.IsOfKind(CodeMethodKind.IndexerBackwardCompatibility),
-            AbstractionsPackageName, "getPathParameters"),
+            AbstractionsPackageName, false, "getPathParameters"),
         new (x => x is CodeMethod method && method.IsOfKind(CodeMethodKind.RequestExecutor),
-            AbstractionsPackageName, "Parsable", "ParsableFactory"),
+            AbstractionsPackageName, true, "Parsable", "ParsableFactory"),
         new (x => x is CodeClass @class && @class.IsOfKind(CodeClassKind.Model),
-            AbstractionsPackageName, "Parsable"),
+            AbstractionsPackageName, true, "Parsable"),
         new (x => x is CodeClass @class && @class.IsOfKind(CodeClassKind.Model) && @class.Properties.Any(x => x.IsOfKind(CodePropertyKind.AdditionalData)),
-            AbstractionsPackageName, "AdditionalDataHolder"),
+            AbstractionsPackageName, true, "AdditionalDataHolder"),
+        new (x => x is CodeMethod method && method.IsOfKind(CodeMethodKind.ClientConstructor) &&
+                    method.Parameters.Any(y => y.IsOfKind(CodeParameterKind.BackingStore)),
+            AbstractionsPackageName, true, "BackingStoreFactory"),
         new (x => x is CodeMethod method && method.IsOfKind(CodeMethodKind.ClientConstructor) &&
                     method.Parameters.Any(y => y.IsOfKind(CodeParameterKind.BackingStore)),
-            AbstractionsPackageName, "BackingStoreFactory", "BackingStoreFactorySingleton"),
+            AbstractionsPackageName, false, "BackingStoreFactorySingleton"),
+        new (x => x is CodeProperty prop && prop.IsOfKind(CodePropertyKind.BackingStore),
+            AbstractionsPackageName, true, "BackingStore", "BackedModel"),
         new (x => x is CodeProperty prop && prop.IsOfKind(CodePropertyKind.BackingStore),
-            AbstractionsPackageName, "BackingStore", "BackedModel", "BackingStoreFactorySingleton"),
-        new (static x => x is CodeMethod method && method.IsOfKind(CodeMethodKind.RequestExecutor, CodeMethodKind.RequestGenerator) && method.Parameters.Any(static y => y.IsOfKind(CodeParameterKind.RequestBody) && y.Type.Name.Equals(MultipartBodyClassName, StringComparison.OrdinalIgnoreCase)),
+            AbstractionsPackageName, false, "BackingStoreFactorySingleton"),
+        new (x => x is CodeMethod m && HasMultipartBody(m),
             AbstractionsPackageName, MultipartBodyClassName, $"serialize{MultipartBodyClassName}")
     };
     private const string MultipartBodyClassName = "MultipartBody";

src/Kiota.Builder/Writers/TypeScript/CodeUsingWriter.cs

@@ -19,17 +19,17 @@ public void WriteCodeElement(IEnumerable<CodeUsing> usings, CodeNamespace parent
         var enumeratedUsings = usings.ToArray();
         var externalImportSymbolsAndPaths = enumeratedUsings
                                                 .Where(static x => x.IsExternal)
-                                                .Select(static x => new { Symbol = x.Name, Alias = string.Empty, Path = x.Declaration?.Name ?? string.Empty, ShouldUseTypeImport = false });
+                                                .Select(static x => new { Symbol = x.Name, Alias = string.Empty, Path = x.Declaration?.Name ?? string.Empty, ShouldUseTypeImport = x.IsErasable });
         var internalImportSymbolsAndPaths = enumeratedUsings
                                                 .Where(static x => !x.IsExternal)
                                                 .Select(x => new { CodeUsingPathTokens = _relativeImportManager.GetRelativeImportPathForUsing(x, parentNamespace), ShouldUseTypeImport = GetShouldUseTypeImport(x) });
         var importSymbolsAndPaths = externalImportSymbolsAndPaths
                                                 .Union(internalImportSymbolsAndPaths.Select(static x => new { Symbol = x.CodeUsingPathTokens.Item1, Alias = x.CodeUsingPathTokens.Item2, Path = x.CodeUsingPathTokens.Item3, x.ShouldUseTypeImport }))
-                                                .GroupBy(static x => x.Path)
-                                                .OrderBy(static x => x.Key);
-        foreach (var codeUsing in importSymbolsAndPaths.Where(static x => !string.IsNullOrWhiteSpace(x.Key)))
+                                                .GroupBy(static x => (x.Path, x.ShouldUseTypeImport))
+                                                .OrderBy(static x => x.Key.Path);
+        foreach (var codeUsing in importSymbolsAndPaths.Where(static x => !string.IsNullOrWhiteSpace(x.Key.Path)))
             writer.WriteLine($"import {codeUsing.Select(x => x.ShouldUseTypeImport ? "type " : "").Distinct().OrderBy(static x => x, StringComparer.Ordinal).Aggregate(static (x, y) => x)}" +
-                $"{{{codeUsing.Select(static x => GetAliasedSymbol(x.Symbol, x.Alias)).Distinct().OrderBy(static x => x, StringComparer.Ordinal).Aggregate(static (x, y) => x + ", " + y)}}} from '{codeUsing.Key}';");
+                $"{{{codeUsing.Select(static x => GetAliasedSymbol(x.Symbol, x.Alias)).Distinct().OrderBy(static x => x, StringComparer.Ordinal).Aggregate(static (x, y) => x + ", " + y)}}} from '{codeUsing.Key.Path}';");
 
         writer.WriteLine();
     }
@@ -41,8 +41,8 @@ public void WriteCodeElement(IEnumerable<CodeUsing> usings, CodeNamespace parent
     **/
     private static bool GetShouldUseTypeImport(CodeUsing codeUsing)
     {
-        // Check if codeUsing.Declaration is an instance of CodeType and if codeType.TypeDefinition is an instance of CodeInterface
-        return codeUsing.Declaration is CodeType codeType && codeType.TypeDefinition is CodeInterface;
+        // Check if codeUsing is Erassable or codeUsing.Declaration is an instance of CodeType and if codeType.TypeDefinition is an instance of CodeInterface
+        return codeUsing.IsErasable || codeUsing.Declaration is CodeType codeType && codeType.TypeDefinition is CodeInterface;
     }
 
     private static string GetAliasedSymbol(string symbol, string alias)

tests/Kiota.Builder.Tests/Writers/TypeScript/CodeUsingWriterTests.cs

@@ -66,7 +66,7 @@ public void DoesntAliasRegularSymbols()
     }
 
     [Fact]
-    public void WritesImportTypeStatement()
+    public void WritesImportTypeStatementForGeneratedInterfaces()
     {
         var usingWriter = new CodeUsingWriter("foo");
         var someInterface = new CodeInterface
@@ -88,4 +88,27 @@ public void WritesImportTypeStatement()
         var result = tw.ToString();
         Assert.Contains("import type {Bar} from", result);
     }
+
+    [Fact]
+    public void WritesImportTypeStatementForDenotedExternalLibraries()
+    {
+        var usingWriter = new CodeUsingWriter("foo");
+        var codeClass = root.AddClass(new CodeClass
+        {
+            Name = "bar",
+        }).First();
+        var us = new CodeUsing
+        {
+            Name = "bar",
+            Declaration = new CodeType
+            {
+                Name = codeClass.Name,
+                TypeDefinition = codeClass,
+            },
+            IsErasable = true,
+        };
+        usingWriter.WriteCodeElement(new CodeUsing[] { us }, root, writer);
+        var result = tw.ToString();
+        Assert.Contains("import type {Bar} from", result);
+    }
 }