removing all typeof x === 'undefined' in favour of x === undefined (#1248)

Author: Janther

src/index.ts

@@ -55,7 +55,7 @@ const antlrCanAttachComment = ({ type }: { type: string }): boolean =>
   typeof type === 'string' && type !== 'BlockComment' && type !== 'LineComment';
 const canAttachComment = (node: AstNode): boolean =>
   typeof node !== 'string' &&
-  typeof node !== 'undefined' &&
+  node !== undefined &&
   node.kind && // Make sure it's not Location
   !isComment(node);
 

src/slang-nodes/ContractSpecifiers.ts

@@ -28,9 +28,9 @@ export class ContractSpecifiers extends SlangNode {
   print(path: AstPath<ContractSpecifiers>, print: PrintFunction): Doc {
     const [specifier1, specifier2] = path.map(print, 'items');
 
-    if (typeof specifier1 === 'undefined') return '';
+    if (specifier1 === undefined) return '';
 
-    if (typeof specifier2 === 'undefined') return [' ', specifier1];
+    if (specifier2 === undefined) return [' ', specifier1];
 
     const groupId = Symbol('Slang.ContractSpecifiers.inheritance');
     return printSeparatedList(

src/slang-nodes/SlangNode.ts

@@ -126,7 +126,7 @@ export class SlangNode {
     // calculate correct loc object
     if (loc.leadingOffset === 0) {
       for (const childNode of childNodes) {
-        if (typeof childNode === 'undefined') continue;
+        if (childNode === undefined) continue;
         const { leadingOffset, start } = childNode.loc;
 
         if (start - leadingOffset === loc.start) {
@@ -139,7 +139,7 @@ export class SlangNode {
 
     if (loc.trailingOffset === 0) {
       for (const childNode of reversedIterator(childNodes)) {
-        if (typeof childNode === 'undefined') continue;
+        if (childNode === undefined) continue;
         const { trailingOffset, end } = childNode.loc;
 
         if (end + trailingOffset === loc.end) {

src/slang-printers/print-comments.ts

@@ -20,7 +20,7 @@ export function printComments(
   path: AstPath<StrictAstNode>,
   options: ParserOptions<AstNode>
 ): Doc[] {
-  if (typeof path.node.comments === 'undefined') return [];
+  if (path.node.comments === undefined) return [];
   return joinExisting(
     line,
     path.map((commentPath, index, comments: Comment[]) => {

src/slang-utils/loc.ts

@@ -1,11 +1,11 @@
 import type { AstNode } from '../slang-nodes/types.d.ts';
 
 export function locStart(node: AstNode): number {
-  if (typeof node === 'string' || typeof node === 'undefined') return -1;
+  if (typeof node === 'string' || node === undefined) return -1;
   return node.loc.start;
 }
 
 export function locEnd(node: AstNode): number {
-  if (typeof node === 'string' || typeof node === 'undefined') return -1;
+  if (typeof node === 'string' || node === undefined) return -1;
   return node.loc.end;
 }