Remove whitespace

src/compiler/checker.ts

@@ -3015,7 +3015,7 @@ namespace ts {
                 const sig = nodeBuilder.signatureToSignatureDeclaration(signature, sigOutput, enclosingDeclaration, toNodeBuilderFlags(flags) | NodeBuilderFlags.IgnoreErrors | NodeBuilderFlags.WriteTypeParametersInQualifiedName);
                 const printer = createPrinter({ removeComments: true, omitTrailingSemicolon: true });
                 const sourceFile = enclosingDeclaration && getSourceFileOfNode(enclosingDeclaration);
-                printer.writeNode(EmitHint.Unspecified, sig!, /*sourceFile*/ sourceFile, writer); // TODO: GH#18217
+                printer.writeNode(EmitHint.Unspecified, sig!, /*sourceFile*/ sourceFile, getTrailingSemicolonOmittingWriter(writer)); // TODO: GH#18217
                 return writer;
             }
         }

src/compiler/commandLineParser.ts

@@ -545,6 +545,12 @@ namespace ts {
             category: Diagnostics.Advanced_Options,
             description: Diagnostics.Show_verbose_diagnostic_information
         },
+        {
+            name: "removeWhitespace",
+            type: "boolean",
+            category: Diagnostics.Advanced_Options,
+            description: Diagnostics.Do_not_emit_insignificant_whitespace_or_insignificant_trailing_semicolons_to_output
+        },
         {
             name: "traceResolution",
             type: "boolean",

src/compiler/comments.ts

@@ -155,13 +155,13 @@ namespace ts {
                 writer.writeLine();
             }
             else {
-                writer.write(" ");
+                writer.writeSpace(" ");
             }
         }
 
         function emitTrailingSynthesizedComment(comment: SynthesizedComment) {
             if (!writer.isAtStartOfLine()) {
-                writer.write(" ");
+                writer.writeSpace(" ");
             }
             writeSynthesizedComment(comment);
             if (comment.hasTrailingNewLine) {
@@ -283,7 +283,7 @@ namespace ts {
                 writer.writeLine();
             }
             else if (kind === SyntaxKind.MultiLineCommentTrivia) {
-                writer.write(" ");
+                writer.writeSpace(" ");
             }
         }
 
@@ -303,7 +303,7 @@ namespace ts {
             if (!shouldWriteComment(currentText, commentPos)) return;
             // trailing comments are emitted at space/*trailing comment1 */space/*trailing comment2*/
             if (!writer.isAtStartOfLine()) {
-                writer.write(" ");
+                writer.writeSpace(" ");
             }
 
             if (emitPos) emitPos(commentPos);
@@ -342,7 +342,7 @@ namespace ts {
                 writer.writeLine();
             }
             else {
-                writer.write(" ");
+                writer.writeSpace(" ");
             }
         }
 

src/compiler/core.ts

@@ -428,8 +428,8 @@ namespace ts {
         array.length = outIndex;
     }
 
-    export function clear(array: {}[]): void {
-        array.length = 0;
+    export function clear(array: {}[] | undefined): void {
+        if (array) array.length = 0;
     }
 
     export function map<T, U>(array: ReadonlyArray<T>, f: (x: T, i: number) => U): U[];

src/compiler/diagnosticMessages.json

@@ -3672,6 +3672,12 @@
         "code": 6205
     },
 
+    "Do not emit insignificant whitespace or insignificant trailing semicolons to output.": {
+        "category": "Message",
+        "code": 6206
+    },
+
+
     "Projects to reference": {
         "category": "Message",
         "code": 6300