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

src/domain/javascript/javascriptSemanticAnalysis.fixture.ts

@@ -0,0 +1,61 @@
+import { expect } from "vitest";
+
+import type {
+  JavaScriptSemanticBinding,
+  JavaScriptSemanticIr,
+} from "./javascriptSemanticIr.js";
+
+export const programScope = (ir: JavaScriptSemanticIr) => {
+  const scope = ir.scopes.find(({ kind }) => kind === "program");
+  if (scope === undefined) throw new Error("Missing program scope");
+  return scope;
+};
+
+export const bindingsNamed = (
+  ir: JavaScriptSemanticIr,
+  name: string,
+): JavaScriptSemanticBinding[] =>
+  ir.bindings.filter(({ name: candidate }) => candidate === name);
+
+export const onlyBinding = (
+  ir: JavaScriptSemanticIr,
+  name: string,
+): JavaScriptSemanticBinding => {
+  const bindings = bindingsNamed(ir, name);
+  expect(bindings).toHaveLength(1);
+  const binding = bindings[0];
+  if (binding === undefined) throw new Error(`Missing binding ${name}`);
+  return binding;
+};
+
+export const onlyCallable = (ir: JavaScriptSemanticIr, name: string) => {
+  const callables = ir.callables.filter(
+    ({ name: candidate }) => candidate === name,
+  );
+  if (callables.length !== 1 || callables[0] === undefined)
+    throw new Error(`Expected one callable named ${name}`);
+  return callables[0];
+};
+
+export const topLevelBinding = (
+  ir: JavaScriptSemanticIr,
+  name: string,
+): JavaScriptSemanticBinding => {
+  const scopeId = programScope(ir).scopeId;
+  const binding = ir.bindings.find(
+    ({ name: candidate, scopeId: candidateScope }) =>
+      candidate === name && candidateScope === scopeId,
+  );
+  if (binding === undefined)
+    throw new Error(`Missing top-level binding ${name}`);
+  return binding;
+};
+
+export const origin = (binding: JavaScriptSemanticBinding) => {
+  expect(binding.provenance.status).toBe("module");
+  expect(binding.provenance.origins).toHaveLength(1);
+  const value = binding.provenance.origins[0];
+  if (value === undefined)
+    throw new Error(`Missing origin for ${binding.name}`);
+  return value;
+};