[Refactor] display-name: use unwrapTSAsExpression

also add `isTSAsExpression` AST util

Author: ljharb

lib/rules/display-name.js

@@ -198,7 +198,7 @@ module.exports = {
         if (!component) {
           return;
         }
-        markDisplayNameAsDeclared(component.node.type === 'TSAsExpression' ? component.node.expression : component.node);
+        markDisplayNameAsDeclared(astUtil.unwrapTSAsExpression(component.node));
       },
 
       'FunctionExpression, FunctionDeclaration, ArrowFunctionExpression'(node) {

lib/util/ast.js

@@ -339,15 +339,18 @@ function isAssignmentLHS(node) {
   );
 }
 
+function isTSAsExpression(node) {
+  return node && node.type === 'TSAsExpression';
+}
+
 /**
  * Extracts the expression node that is wrapped inside a TS type assertion
  *
  * @param {ASTNode} node - potential TS node
  * @returns {ASTNode} - unwrapped expression node
  */
 function unwrapTSAsExpression(node) {
-  if (node && node.type === 'TSAsExpression') return node.expression;
-  return node;
+  return isTSAsExpression(node) ? node.expression : node;
 }
 
 function isTSTypeReference(node) {
@@ -450,6 +453,7 @@ module.exports = {
   isFunctionLike,
   inConstructor,
   isNodeFirstInLine,
+  isTSAsExpression,
   unwrapTSAsExpression,
   traverseReturns,
   isTSTypeReference,