feat: add getValues function for extracting literal values from TypeScript types

Author: nicosammito

src/util/values.util.ts

@@ -0,0 +1,71 @@
+import ts, { NumberLiteralType, StringLiteralType } from "typescript";
+import { LiteralValue } from "@code0-tech/sagittarius-graphql-types";
+
+/**
+ * Extracts literal values from a TypeScript type.
+ *
+ * This function recursively processes TypeScript types and extracts all literal values,
+ * including string literals, number literals, and boolean literals. For union types,
+ * it flattens and combines all literal values from each constituent type.
+ *
+ * @param type - The TypeScript type to extract values from
+ * @returns An array of LiteralValue objects representing all literal values found in the type
+ *
+ * @example
+ * // For a type like "red" | "blue" | 42
+ * const values = getValues(type);
+ * // Returns:
+ * // [
+ * //   { value: "red", __typename: "LiteralValue" },
+ * //   { value: "blue", __typename: "LiteralValue" },
+ * //   { value: "42" }
+ * // ]
+ */
+export const getValues = (type: ts.Type): LiteralValue[] => {
+  // Handle union types by recursively extracting values from each constituent type
+  if (type.isUnion()) {
+    return type.types.flatMap(getValues);
+  }
+
+  // Extract string literal values
+  if (type.isStringLiteral()) {
+    return [
+      {
+        value: (type as StringLiteralType).value,
+        __typename: "LiteralValue",
+      },
+    ];
+  }
+
+  // Extract number literal values, converting to string representation
+  if (type.isNumberLiteral()) {
+    return [
+      {
+        value: (type as NumberLiteralType).value.toString(),
+      },
+    ];
+  }
+
+  // Extract boolean true literal values
+  if ((type as any).intrinsicName === "true") {
+    return [
+      {
+        value: "true",
+        __typename: "LiteralValue",
+      },
+    ];
+  }
+
+  // Extract boolean false literal values
+  if ((type as any).intrinsicName === "false") {
+    return [
+      {
+        value: "false",
+        __typename: "LiteralValue",
+      },
+    ];
+  }
+
+  // Return empty array if no literal values are found
+  return [];
+};