feat: toJSON

nix-js/runtime-ts/src/builtins/conversion.ts

@@ -7,6 +7,7 @@ import { isStringWithContext } from "../types";
 import { force } from "../thunk";
 import { type NixStringContext, mkStringWithContext, addBuiltContext } from "../string-context";
 import { forceFunction } from "../type-assert";
+import { nixValueToJson } from "../conversion";
 
 const convertJsonToNix = (json: unknown): NixValue => {
   if (json === null) {
@@ -55,8 +56,13 @@ export const fromTOML = (e: NixValue): never => {
   throw new Error("Not implemented: fromTOML");
 };
 
-export const toJSON = (e: NixValue): never => {
-  throw new Error("Not implemented: toJSON");
+export const toJSON = (e: NixValue): NixString => {
+  const context: Set<string> = new Set();
+  const string = JSON.stringify(nixValueToJson(e, new Set(), context));
+  if (context.size === 0) {
+    return string;
+  }
+  return mkStringWithContext(string, context);
 };
 
 export const toXML = (e: NixValue): never => {

nix-js/runtime-ts/src/builtins/derivation.ts

@@ -9,6 +9,7 @@ import {
   isStringWithContext,
   HAS_CONTEXT,
 } from "../string-context";
+import { nixValueToJson } from "../conversion";
 
 const forceAttrs = (value: NixValue): NixAttrs => {
   const forced = force(value);
@@ -80,57 +81,6 @@ const extractArgs = (attrs: NixAttrs, outContext: NixStringContext): string[] =>
   return argsList.map((a) => coerceToString(a, StringCoercionMode.ToString, false, outContext));
 };
 
-const nixValueToJson = (value: NixValue, seen = new Set<object>(), outContext?: NixStringContext): any => {
-  const v = force(value);
-
-  if (v === null) return null;
-  if (typeof v === "boolean") return v;
-  if (typeof v === "string") return v;
-  if (typeof v === "number") return v;
-
-  if (typeof v === "object" && HAS_CONTEXT in v && "context" in v) {
-    if (outContext) {
-      for (const elem of v.context) {
-        outContext.add(elem);
-      }
-    }
-    return v.value;
-  }
-
-  if (typeof v === "bigint") {
-    const num = Number(v);
-    if (v > Number.MAX_SAFE_INTEGER || v < Number.MIN_SAFE_INTEGER) {
-      console.warn(`derivation: integer ${v} exceeds safe range, precision may be lost in __structuredAttrs`);
-    }
-    return num;
-  }
-
-  if (typeof v === "object" && v !== null) {
-    if (seen.has(v)) {
-      throw new Error("derivation: circular reference detected in __structuredAttrs");
-    }
-    seen.add(v);
-  }
-
-  if (Array.isArray(v)) {
-    return v.map((item) => nixValueToJson(item, seen, outContext));
-  }
-
-  if (typeof v === "object") {
-    const result: Record<string, any> = {};
-    for (const [key, val] of Object.entries(v)) {
-      result[key] = nixValueToJson(val, seen, outContext);
-    }
-    return result;
-  }
-
-  if (typeof v === "function") {
-    throw new Error("derivation: cannot serialize function in __structuredAttrs");
-  }
-
-  throw new Error(`derivation: cannot serialize ${typeof v} to JSON`);
-};
-
 const extractEnv = (
   attrs: NixAttrs,
   structuredAttrs: boolean,

nix-js/runtime-ts/src/builtins/index.ts

@@ -249,7 +249,7 @@ export const builtins: any = {
 
   builtins: createThunk(() => builtins),
   currentSystem: createThunk(() => {
-    return "x86_64-linux"
+    return "x86_64-linux";
   }),
   currentTime: createThunk(() => Date.now()),
 

nix-js/runtime-ts/src/conversion.ts

@@ -0,0 +1,58 @@
+import { HAS_CONTEXT, NixStringContext } from "./string-context";
+import { force } from "./thunk";
+import type { NixValue } from "./types";
+
+export const nixValueToJson = (
+  value: NixValue,
+  seen = new Set<object>(),
+  outContext?: NixStringContext,
+): any => {
+  const v = force(value);
+
+  if (v === null) return null;
+  if (typeof v === "boolean") return v;
+  if (typeof v === "string") return v;
+  if (typeof v === "number") return v;
+
+  if (typeof v === "object" && HAS_CONTEXT in v && "context" in v) {
+    if (outContext) {
+      for (const elem of v.context) {
+        outContext.add(elem);
+      }
+    }
+    return v.value;
+  }
+
+  if (typeof v === "bigint") {
+    const num = Number(v);
+    if (v > Number.MAX_SAFE_INTEGER || v < Number.MIN_SAFE_INTEGER) {
+      console.warn(`derivation: integer ${v} exceeds safe range, precision may be lost in __structuredAttrs`);
+    }
+    return num;
+  }
+
+  if (typeof v === "object" && v !== null) {
+    if (seen.has(v)) {
+      throw new Error("derivation: circular reference detected in __structuredAttrs");
+    }
+    seen.add(v);
+  }
+
+  if (Array.isArray(v)) {
+    return v.map((item) => nixValueToJson(item, seen, outContext));
+  }
+
+  if (typeof v === "object") {
+    const result: Record<string, any> = {};
+    for (const [key, val] of Object.entries(v)) {
+      result[key] = nixValueToJson(val, seen, outContext);
+    }
+    return result;
+  }
+
+  if (typeof v === "function") {
+    throw new Error("derivation: cannot serialize function in __structuredAttrs");
+  }
+
+  throw new Error(`derivation: cannot serialize ${typeof v} to JSON`);
+};