Npx Sync

1import { existsSync } from "node:fs";
2import { dirname, join } from "node:path";
3
4function resolveNpxCliPath(env, pathExists) {
5  const npmExecPath = env.npm_execpath;
6  const nodeExecPath = env.npm_node_execpath || process.execPath;
7  if (npmExecPath) {
8    const fileName = npmExecPath.replace(/\\/g, "/").split("/").pop()?.toLowerCase();
9    const candidate =
10      fileName === "npx-cli.js" ? npmExecPath : join(dirname(npmExecPath), "npx-cli.js");
11    if (pathExists(candidate)) return candidate;
12  }
13  const besideNode = join(dirname(nodeExecPath), "node_modules", "npm", "bin", "npx-cli.js");
14  return pathExists(besideNode) ? besideNode : null;
15}
16
17// Sync-spawn analog of the audio engine's spawnP, for execFileSync call sites
18// that must hard-fail (rather than fall through to another provider) when npx
19// cannot be resolved. On Windows a bare "npx" is npx.cmd, which
20// execFileSync/spawnSync cannot exec (spawnSync npx ENOENT) —
21// resolveSpawnCommand reroutes it through node + npx-cli.js, no shell:true.
22//
23// `platform`/`env`/`pathExists` params (defaulting to the real values) exist
24// so tests can exercise the win32 branch without mocking node:child_process
25// (its ESM exports are non-configurable) — same idiom as spawnP and
26// localTtsGenerate.
27export function resolveNpxInvocation(
28  argv,
29  opts,
30  platform = process.platform,
31  env = process.env,
32  pathExists = existsSync,
33) {
34  const resolved =
35    platform !== "win32"
36      ? { cmd: "npx", args: argv, opts: { stdio: "ignore", ...opts } }
37      : (() => {
38          const nodeExecPath = env.npm_node_execpath || process.execPath;
39          const npxCliPath = resolveNpxCliPath(env, pathExists);
40          return npxCliPath
41            ? {
42                cmd: nodeExecPath,
43                args: [npxCliPath, ...argv.map((arg) => String(arg))],
44                opts: { stdio: "ignore", windowsHide: true, ...opts },
45              }
46            : null;
47        })();
48  if (!resolved) {
49    // npx-on-win32 with no resolvable npx-cli.js — same terminal condition
50    // spawnP warns about, surfaced as a throw for callers with no fallback.
51    throw new Error(
52      "cannot run npx on Windows: npm's npx-cli.js was not found " +
53        "(install npm with Node, or run via npx/npm run so npm_execpath is set)",
54    );
55  }
56  return resolved;
57}