copy comments from template literal to string

Author: bigaru

src/services/refactors/convertStringOrTemplateLiteral.ts

@@ -69,12 +69,20 @@ namespace ts.refactor.convertStringOrTemplateLiteral {
         return textChanges.ChangeTracker.with(context, t => t.replaceNode(context.file, maybeBinary, templateLiteral));
     }
 
+    const templateSpanToExpressions = (file: SourceFile) => (templateSpan: TemplateSpan): Expression[] => {
+        const { expression, literal } = templateSpan;
+        const text = literal.text;
+        copyTrailingAsLeadingComments(templateSpan, expression, file, SyntaxKind.MultiLineCommentTrivia, /* hasTrailingNewLine */ false);
+        return text.length === 0 ? [expression] : [expression, createStringLiteral(text)];
+    };
+
     function getEditsForToStringConcatenation(context: RefactorContext, node: Node) {
         const templateLiteral = findAncestor(node, n => isTemplateLiteral(n))! as TemplateLiteral;
 
         if (isTemplateExpression(templateLiteral)) {
             const { head, templateSpans } = templateLiteral;
-            const arrayOfNodes = templateSpans.map(templateSpanToExpressions)
+            const spanToExpressionWithComment = templateSpanToExpressions(context.file);
+            const arrayOfNodes = templateSpans.map(spanToExpressionWithComment)
                                               .reduce((accumulator, nextArray) => accumulator.concat(nextArray));
 
             if (head.text.length !== 0) arrayOfNodes.unshift(createStringLiteral(head.text));
@@ -88,12 +96,6 @@ namespace ts.refactor.convertStringOrTemplateLiteral {
         }
     }
 
-    function templateSpanToExpressions(templateSpan: TemplateSpan): Expression[] {
-        const { expression, literal } = templateSpan;
-        const text = literal.text;
-        return text.length === 0 ? [expression] : [expression, createStringLiteral(text)];
-    }
-
     function isNotEqualsOperator(node: BinaryExpression) {
         return node.operatorToken.kind !== SyntaxKind.EqualsToken;
     }

tests/cases/fourslash/refactorConvertStringOrTemplateLiteral_ToStringComment.ts

@@ -0,0 +1,13 @@
+/// <reference path='fourslash.ts' />
+
+//// const foo = `/*x*/H/*y*/EAD ${ /* C0 */ 42 /* C1 */} Span1 ${ /* C2 */ 43 /* C3 */} Span2 ${ /* C4 */ 44 /* C5 */} Span3`
+
+goTo.select("x", "y");
+edit.applyRefactor({
+    refactorName: "Convert string concatenation or template literal",
+    actionName: "Convert to string concatenation",
+    actionDescription: "Convert to string concatenation",
+    newContent:
+`const foo = "HEAD " + /* C0 */ 42 /* C1 */ + " Span1 " + /* C2 */ 43 /* C3 */ + " Span2 " + /* C4 */ 44 /* C5 */ + " Span3"`,
+});
+

tests/cases/fourslash/refactorConvertStringOrTemplateLiteral_ToStringCommentOnlyExpr.ts

@@ -0,0 +1,13 @@
+/// <reference path='fourslash.ts' />
+
+//// const foo = /*x*/`/*y*/${/* C0 */ 42 /* C1 */}`
+
+goTo.select("x", "y");
+edit.applyRefactor({
+    refactorName: "Convert string concatenation or template literal",
+    actionName: "Convert to string concatenation",
+    actionDescription: "Convert to string concatenation",
+    newContent:
+`const foo = /* C0 */ 42 /* C1 */`,
+});
+

tests/cases/fourslash/refactorConvertStringOrTemplateLiteral_ToStringCommentWithoutStr.ts

@@ -0,0 +1,13 @@
+/// <reference path='fourslash.ts' />
+
+//// const foo = `/*x*/H/*y*/EAD | ${ /* C0 */ 42 /* C1 */}${ /* C2 */ 43 /* C3 */}${ /* C4 */ 44 /* C5 */}`
+
+goTo.select("x", "y");
+edit.applyRefactor({
+    refactorName: "Convert string concatenation or template literal",
+    actionName: "Convert to string concatenation",
+    actionDescription: "Convert to string concatenation",
+    newContent:
+`const foo = "HEAD | " + /* C0 */ 42 /* C1 */ + /* C2 */ 43 /* C3 */ + /* C4 */ 44 /* C5 */`,
+});
+

tests/cases/fourslash/refactorConvertStringOrTemplateLiteral_ToTemplateComment.ts

@@ -0,0 +1,13 @@
+/// <reference path='fourslash.ts' />
+
+//// const foo = /* C0 */ /*x*/"/*y*/foobar" /* C1 */ + " is" /* C2 */ + 42 /* C3 */ + "years old" /* C4 */
+
+goTo.select("x", "y");
+edit.applyRefactor({
+    refactorName: "Convert string concatenation or template literal",
+    actionName: "Convert to template literal",
+    actionDescription: "Convert to template literal",
+    newContent:
+`const foo = /* C0 */ \`foobar is \${ /* C1 */ /* C2 */ 42 /* C3 */}years old\` /* C4 */`,
+});
+