refactor(lexer): handle newline lexing in consumeNewline function

graphql · Dec 28, 2018 · 06ae24b · 06ae24b
1 parent a44dcf8
commit 06ae24b
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Showing 2 changed files with 54 additions and 37 deletions.
diff --git a/src/language/__tests__/lexer-test.js b/src/language/__tests__/lexer-test.js
@@ -365,7 +365,7 @@ describe('Lexer', () => {
     });
   });
 
-  it('advance line after lexing block string', () => {
+  it('advance line after lexing multiline block string', () => {
     expect(
       lexSecond(`"""
 

diff --git a/src/language/lexer.js b/src/language/lexer.js
@@ -361,6 +361,34 @@ function unexpectedCharacterMessage(code) {
   return `Cannot parse the unexpected character ${printCharCode(code)}.`;
 }
 
+function consumeNewline(
+  startPosition: number,
+  code: number,
+  codeahead: number,
+  lexer: Lexer<*>,
+): [boolean, number] {
+  let position = startPosition;
+  let consumed = false;
+  if (code === 10) {
+    // new line
+    ++position;
+    ++lexer.line;
+    lexer.lineStart = position;
+    consumed = true;
+  } else if (code === 13) {
+    // carriage return
+    if (codeahead === 10) {
+      position += 2;
+    } else {
+      ++position;
+    }
+    ++lexer.line;
+    lexer.lineStart = position;
+    consumed = true;
+  }
+  return [consumed, position];
+}
+
 /**
  * Reads from body starting at startPosition until it finds a non-whitespace
  * character, then returns the position of that character for lexing.
@@ -377,22 +405,17 @@ function positionAfterWhitespace(
     // tab | space | comma | BOM
     if (code === 9 || code === 32 || code === 44 || code === 0xfeff) {
       ++position;
-    } else if (code === 10) {
-      // new line
-      ++position;
-      ++lexer.line;
-      lexer.lineStart = position;
-    } else if (code === 13) {
-      // carriage return
-      if (charCodeAt.call(body, position + 1) === 10) {
-        position += 2;
-      } else {
-        ++position;
-      }
-      ++lexer.line;
-      lexer.lineStart = position;
     } else {
-      break;
+      const [consumed, positionAfterNewLine] = consumeNewline(
+        position,
+        code,
+        charCodeAt.call(body, position + 1),
+        lexer,
+      );
+      if (!consumed) {
+        break;
+      }
+      position = positionAfterNewLine;
     }
   }
   return position;
@@ -636,12 +659,11 @@ function readBlockString(source, start, line, col, prev, lexer): Token {
     position < body.length &&
     (code = charCodeAt.call(body, position)) !== null
   ) {
+    const code1ahead = charCodeAt.call(body, position + 1);
+    const code2ahead = charCodeAt.call(body, position + 2);
+
     // Closing Triple-Quote (""")
-    if (
-      code === 34 &&
-      charCodeAt.call(body, position + 1) === 34 &&
-      charCodeAt.call(body, position + 2) === 34
-    ) {
+    if (code === 34 && code1ahead === 34 && code2ahead === 34) {
       rawValue += slice.call(body, chunkStart, position);
       return new Tok(
         TokenKind.BLOCK_STRING,
@@ -668,25 +690,20 @@ function readBlockString(source, start, line, col, prev, lexer): Token {
       );
     }
 
-    if (code === 10) {
-      // new line
-      ++position;
-      ++lexer.line;
-      lexer.lineStart = position;
-    } else if (code === 13) {
-      // carriage return
-      if (charCodeAt.call(body, position + 1) === 10) {
-        position += 2;
-      } else {
-        ++position;
-      }
-      ++lexer.line;
-      lexer.lineStart = position;
+    const [isNewline, positionAfterNewLine] = consumeNewline(
+      position,
+      code,
+      code1ahead,
+      lexer,
+    );
+
+    if (isNewline) {
+      position = positionAfterNewLine;
     } else if (
       // Escape Triple-Quote (\""")
       code === 92 &&
-      charCodeAt.call(body, position + 1) === 34 &&
-      charCodeAt.call(body, position + 2) === 34 &&
+      code1ahead === 34 &&
+      code2ahead === 34 &&
       charCodeAt.call(body, position + 3) === 34
     ) {
       rawValue += slice.call(body, chunkStart, position) + '"""';