add isLiteralExpressionValue utility

.changeset/ten-geckos-relate.md

@@ -0,0 +1,9 @@
+---
+'@tsxmod/utils': minor
+---
+
+Adds `isLiteralExpressionValue` utility to help determine if a literal expression value was resolved or not since `undefined` is a valid value.
+
+```ts
+
+```

packages/utils/src/expressions/index.ts

@@ -1,5 +1,6 @@
 export {
   resolveLiteralExpression,
+  isLiteralExpressionValue,
   type LiteralExpressionValue,
 } from './resolveLiteralExpression'
 export { resolveObjectLiteralExpression } from './resolveObjectLiteralExpression'

packages/utils/src/expressions/resolveLiteralExpression.ts

@@ -11,10 +11,15 @@ export type LiteralExpressionValue =
   | Record<string, any>
   | LiteralExpressionValue[]
 
+const EMPTY_LITERAL_EXPRESSION_VALUE = Symbol('EMPTY_LITERAL_EXPRESSION_VALUE')
+
 /** Recursively resolves an expression into a literal value. */
 export function resolveLiteralExpression(
   expression: Expression
-): LiteralExpressionValue | LiteralExpressionValue[] | undefined {
+):
+  | LiteralExpressionValue
+  | LiteralExpressionValue[]
+  | typeof EMPTY_LITERAL_EXPRESSION_VALUE {
   if (Node.isNullLiteral(expression)) {
     return null
   }
@@ -65,4 +70,13 @@ export function resolveLiteralExpression(
   if (Node.isSpreadElement(expression) || Node.isAsExpression(expression)) {
     return resolveLiteralExpression(expression.getExpression())
   }
+
+  return EMPTY_LITERAL_EXPRESSION_VALUE
+}
+
+/** Determines when a value was resolved in `resolveLiteralExpression`. */
+export function isLiteralExpressionValue(
+  value: ReturnType<typeof resolveLiteralExpression>
+) {
+  return value !== EMPTY_LITERAL_EXPRESSION_VALUE
 }