Allow multiline string literals as JSX attribute values.

common/define-grammar.js

@@ -2,6 +2,7 @@ const PREC = {
   ACCESSIBILITY: 1,
   DEFINITION: 1,
   DECLARATION: 1,
+  STRING: 2, // must match the value defined in javascript's grammar.js.
   INTERSECTION: 2,
   UNION: 2,
   PLUS: 4,
@@ -156,6 +157,34 @@ module.exports = function defineGrammar(dialect) {
         '>'
       )),
 
+      // Use more tolerant $.tsx_string instead of $.string.
+      _jsx_attribute_value: ($, previous) => choice(
+        ...previous.members.map(member =>
+          member.name == 'string' ? $.tsx_string : member
+      )),
+
+      // Same as $.string defined for javascript, with modified regexp
+      // that allows unescaped newlines.
+      // See https://github.com/Microsoft/TypeScript/issues/13328
+      tsx_string: $ => choice(
+        seq(
+          '"',
+          repeat(choice(
+            token.immediate(prec(PREC.STRING, /[^"\\\n]+|\\?\r?\n/)),
+            $.escape_sequence
+          )),
+          '"'
+        ),
+        seq(
+          "'",
+          repeat(choice(
+            token.immediate(prec(PREC.STRING, /[^'\\\n]+|\\?\r?\n/)),
+            $.escape_sequence
+          )),
+          "'"
+        )
+      ),
+
       _import_export_specifier: ($, previous) => seq(
         optional(choice('type', 'typeof')),
         previous

tsx/corpus/expressions.txt

@@ -12,3 +12,25 @@ Type arguments in JSX
       (jsx_opening_element (identifier) (type_arguments (type_identifier)))
       (jsx_text)
       (jsx_closing_element (identifier)))))
+
+==========================================================
+TSX string literals
+==========================================================
+
+<Element attr="hello
+               world">
+</Element>;
+
+---
+
+(program
+  (expression_statement
+    (jsx_element
+      (jsx_opening_element
+        (identifier)
+        (jsx_attribute
+          (property_identifier)
+          (tsx_string)))
+      (jsx_text)
+      (jsx_closing_element
+        (identifier)))))

tsx/src/grammar.json

@@ -2624,7 +2624,7 @@
       "members": [
         {
           "type": "SYMBOL",
-          "name": "string"
+          "name": "tsx_string"
         },
         {
           "type": "SYMBOL",
@@ -6565,6 +6565,83 @@
         }
       ]
     },
+    "tsx_string": {
+      "type": "CHOICE",
+      "members": [
+        {
+          "type": "SEQ",
+          "members": [
+            {
+              "type": "STRING",
+              "value": "\""
+            },
+            {
+              "type": "REPEAT",
+              "content": {
+                "type": "CHOICE",
+                "members": [
+                  {
+                    "type": "IMMEDIATE_TOKEN",
+                    "content": {
+                      "type": "PREC",
+                      "value": 2,
+                      "content": {
+                        "type": "PATTERN",
+                        "value": "[^\"\\\\\\n]+|\\\\?\\r?\\n"
+                      }
+                    }
+                  },
+                  {
+                    "type": "SYMBOL",
+                    "name": "escape_sequence"
+                  }
+                ]
+              }
+            },
+            {
+              "type": "STRING",
+              "value": "\""
+            }
+          ]
+        },
+        {
+          "type": "SEQ",
+          "members": [
+            {
+              "type": "STRING",
+              "value": "'"
+            },
+            {
+              "type": "REPEAT",
+              "content": {
+                "type": "CHOICE",
+                "members": [
+                  {
+                    "type": "IMMEDIATE_TOKEN",
+                    "content": {
+                      "type": "PREC",
+                      "value": 2,
+                      "content": {
+                        "type": "PATTERN",
+                        "value": "[^'\\\\\\n]+|\\\\?\\r?\\n"
+                      }
+                    }
+                  },
+                  {
+                    "type": "SYMBOL",
+                    "name": "escape_sequence"
+                  }
+                ]
+              }
+            },
+            {
+              "type": "STRING",
+              "value": "'"
+            }
+          ]
+        }
+      ]
+    },
     "non_null_expression": {
       "type": "PREC_LEFT",
       "value": 10,

tsx/src/node-types.json

@@ -3283,7 +3283,7 @@
           "named": true
         },
         {
-          "type": "string",
+          "type": "tsx_string",
           "named": true
         }
       ]
@@ -5078,6 +5078,21 @@
       }
     }
   },
+  {
+    "type": "tsx_string",
+    "named": true,
+    "fields": {},
+    "children": {
+      "multiple": true,
+      "required": false,
+      "types": [
+        {
+          "type": "escape_sequence",
+          "named": true
+        }
+      ]
+    }
+  },
   {
     "type": "tuple_type",
     "named": true,
@@ -6314,11 +6329,11 @@
   },
   {
     "type": "number",
-    "named": false
+    "named": true
   },
   {
     "type": "number",
-    "named": true
+    "named": false
   },
   {
     "type": "of",