fix: improve edge cases of literalToAst

src/proxy/_utils.ts

@@ -46,15 +46,22 @@ export function proxify<T>(node: ESNode): Proxified<T> {
 const PROXY_KEY = "__magicast_proxy";
 
 export function literalToAst(value: any): ESNode {
-  if (value[PROXY_KEY]) {
-    return value.$ast;
+  if (value === undefined) {
+    return recast.types.builders.identifier("undefined") as any;
+  }
+  if (value === null) {
+    // eslint-disable-next-line unicorn/no-null
+    return  recast.types.builders.literal(null) as any;
   }
   if (Array.isArray(value)) {
     return recast.types.builders.arrayExpression(
       value.map((n) => literalToAst(n)) as any
     ) as any;
   }
   if (typeof value === "object") {
+    if (PROXY_KEY in value) {
+      return value.$ast;
+    }
     return recast.types.builders.objectExpression(
       Object.entries(value).map(([key, value]) => {
         return recast.types.builders.property(

test/utils.test.ts

@@ -0,0 +1,23 @@
+import { describe, it, expect } from "vitest";
+import { print } from "recast";
+import { literalToAst } from "../src/proxy/_utils";
+
+describe('literalToAst', () => {
+  // eslint-disable-next-line unicorn/consistent-function-scoping
+  function run(value: any) {
+    return print(literalToAst(value)).code;
+  }
+
+  it('should work', () => {
+    expect(run(1)).toMatchInlineSnapshot('"1"')
+    expect(run(true)).toMatchInlineSnapshot('"true"')
+    expect(run(undefined)).toMatchInlineSnapshot('"undefined"')
+    // eslint-disable-next-line unicorn/no-null
+    expect(run(null)).toMatchInlineSnapshot('"null"')
+    expect(run([undefined, 1, { foo:'bar' }])).toMatchInlineSnapshot(`
+      "[undefined, 1, {
+          foo: \\"bar\\"
+      }]"
+    `)
+  })
+})