Store scanning information whether JSXText is just an all whitespaces

Author: Kanchalai Tanglertsampan

src/compiler/checker.ts

@@ -13318,8 +13318,13 @@ namespace ts {
                 for (const child of (parent as JsxElement).children) {
                     // In React, JSX text that contains only whitespaces will be ignored so we don't want to type-check that
                     // because then type of children property will have constituent of string type.
-                    if (child.kind !== SyntaxKind.JsxTextAllWhiteSpaces) {
-                        childrenTypes.push(child.kind === SyntaxKind.JsxText ? stringType : checkExpression(child as Expression, checkMode));
+                    if (child.kind === SyntaxKind.JsxText) {
+                        if (!child.containsOnlyWhiteSpaces) {
+                            childrenTypes.push(stringType);
+                        }
+                    }
+                    else {
+                        childrenTypes.push(checkExpression(child, checkMode));
                     }
                 }
                 childrenPropSymbol.type = getUnionType(childrenTypes,  /*subtypeReduction*/ false);

src/compiler/parser.ts

@@ -3825,7 +3825,8 @@ namespace ts {
         }
 
         function parseJsxText(): JsxText {
-            const node = <JsxText>createNode(currentToken, scanner.getStartPos());
+            const node = <JsxText>createNode(SyntaxKind.JsxText, scanner.getStartPos());
+            node.containsOnlyWhiteSpaces = currentToken === SyntaxKind.JsxTextAllWhiteSpaces;
             currentToken = scanner.scanJsxToken();
             return finishNode(node);
         }

src/compiler/scanner.ts

@@ -1729,7 +1729,6 @@ namespace ts {
             // firstNonWhitespace = 0 to indicate that we want leading whitspace,
 
             while (pos < end) {
-                pos++;
                 char = text.charCodeAt(pos);
                 if (char === CharacterCodes.openBrace) {
                     break;
@@ -1754,6 +1753,7 @@ namespace ts {
                 else if (!isWhiteSpaceSingleLine(char)) {
                     firstNonWhitespace = pos;
                 }
+                pos++;
             }
 
             return firstNonWhitespace === -1 ? SyntaxKind.JsxTextAllWhiteSpaces : SyntaxKind.JsxText;

src/compiler/types.ts

@@ -1572,7 +1572,8 @@
     }
 
     export interface JsxText extends Node {
-        kind: SyntaxKind.JsxText;
+        kind: SyntaxKind.JsxText,
+        containsOnlyWhiteSpaces: boolean,
         parent?: JsxElement;
     }