diff --git a/packages/babel-parser/src/parser/statement.js b/packages/babel-parser/src/parser/statement.js
index ea5b295a9dab..a3e17975d1eb 100644
--- a/packages/babel-parser/src/parser/statement.js
+++ b/packages/babel-parser/src/parser/statement.js
@@ -629,9 +629,7 @@ export default class StatementParser extends ExpressionParser {
 
   parseThrowStatement(node: N.ThrowStatement): N.ThrowStatement {
     this.next();
-    if (
-      lineBreak.test(this.input.slice(this.state.lastTokEnd, this.state.start))
-    ) {
+    if (this.hasPrecedingLineBreak()) {
       this.raise(this.state.lastTokEnd, Errors.NewlineAfterThrow);
     }
     node.argument = this.parseExpression();
diff --git a/packages/babel-parser/src/tokenizer/context.js b/packages/babel-parser/src/tokenizer/context.js
index 101ac725969a..ebf8b98fd638 100644
--- a/packages/babel-parser/src/tokenizer/context.js
+++ b/packages/babel-parser/src/tokenizer/context.js
@@ -5,7 +5,6 @@
 // See https://github.com/mozilla/sweet.js/wiki/design
 
 import { types as tt } from "./types";
-import { lineBreak } from "../util/whitespace";
 
 export class TokContext {
   constructor(
@@ -111,10 +110,7 @@ tt._function.updateContext = tt._class.updateContext = function (prevType) {
     prevType.beforeExpr &&
     prevType !== tt.semi &&
     prevType !== tt._else &&
-    !(
-      prevType === tt._return &&
-      lineBreak.test(this.input.slice(this.state.lastTokEnd, this.state.start))
-    ) &&
+    !(prevType === tt._return && this.hasPrecedingLineBreak()) &&
     !(
       (prevType === tt.colon || prevType === tt.braceL) &&
       this.curContext() === types.b_stat
diff --git a/packages/babel-parser/src/tokenizer/index.js b/packages/babel-parser/src/tokenizer/index.js
index d8104c4f9b45..cbc0efab0fe8 100644
--- a/packages/babel-parser/src/tokenizer/index.js
+++ b/packages/babel-parser/src/tokenizer/index.js
@@ -114,6 +114,7 @@ export default class Tokenizer extends ParserErrors {
   // Forward-declarations
   // parser/util.js
   /*::
+  +hasPrecedingLineBreak: () => boolean;
   +unexpected: (pos?: ?number, messageOrType?: string | TokenType) => empty;
   +expectPlugin: (name: string, pos?: ?number) => true;
   */
@@ -603,10 +604,7 @@ export default class Tokenizer extends ParserErrors {
         next === charCodes.dash &&
         !this.inModule &&
         this.input.charCodeAt(this.state.pos + 2) === charCodes.greaterThan &&
-        (this.state.lastTokEnd === 0 ||
-          lineBreak.test(
-            this.input.slice(this.state.lastTokEnd, this.state.pos),
-          ))
+        (this.state.lastTokEnd === 0 || this.hasPrecedingLineBreak())
       ) {
         // A `-->` line comment
         this.skipLineComment(3);
@@ -1525,9 +1523,7 @@ export default class Tokenizer extends ParserErrors {
       prevType === tt._return ||
       (prevType === tt.name && this.state.exprAllowed)
     ) {
-      return lineBreak.test(
-        this.input.slice(this.state.lastTokEnd, this.state.start),
-      );
+      return this.hasPrecedingLineBreak();
     }
 
     if (