refactor(javascript): group domain semantics and contracts (#907)

src/domain/javascript/javascriptAstValues.ts

@@ -0,0 +1,33 @@
+import * as t from "@babel/types";
+
+/** Read an identifier or literal property name without evaluating syntax. */
+export const propertyName = (node: t.Node): string => {
+  if (t.isIdentifier(node)) return node.name;
+  if (t.isStringLiteral(node) || t.isNumericLiteral(node))
+    return String(node.value);
+  return "";
+};
+
+/** Read a property name only when its syntax commits to one exact key. */
+export const semanticStaticPropertyName = (
+  property: t.Node,
+  computed: boolean,
+): string => semanticStaticPropertyKey(property, computed) ?? "";
+
+/** Read an exact property key, preserving the legal empty-string key. */
+export const semanticStaticPropertyKey = (
+  property: t.Node,
+  computed: boolean,
+): string | null => {
+  if (t.isStringLiteral(property) || t.isNumericLiteral(property))
+    return String(property.value);
+  return !computed && t.isIdentifier(property) ? property.name : null;
+};
+
+/**
+ * Display an exact JavaScript string as nonempty label text. Graph labels and
+ * artifact-local keys are nonempty, so the legal empty value is shown as `""`;
+ * producers keep the exact value in their properties.
+ */
+export const javascriptDisplayText = (value: string): string =>
+  value === "" ? '""' : value;