feat: pass origin error as ProcessOuput cause

Author: antongolub

.size-limit.json

@@ -2,7 +2,7 @@
   {
     "name": "zx/core",
     "path": ["build/core.cjs", "build/util.cjs", "build/vendor-core.cjs"],
-    "limit": "77.5 kB",
+    "limit": "77.6 kB",
     "brotli": false,
     "gzip": false
   },
@@ -30,7 +30,7 @@
   {
     "name": "all",
     "path": "build/*",
-    "limit": "850 kB",
+    "limit": "850.2 kB",
     "brotli": false,
     "gzip": false
   }

src/core.ts

@@ -675,6 +675,7 @@ type ProcessDto = {
 
 export class ProcessOutput extends Error {
   private readonly _dto: ProcessDto
+  cause: Error | null
   constructor(dto: ProcessDto)
   constructor(
     code: number | null,
@@ -703,7 +704,9 @@ export class ProcessOutput extends Error {
       ? code
       : { code, signal, duration, error, from, store }
 
+    this.cause = error
     Object.defineProperties(this, {
+      cause: { value: dto.error, enumerable: false, writable: true, configurable: true },
       stdout: { get: once(() => bufArrJoin(dto.store.stdout)) },
       stderr: { get: once(() => bufArrJoin(dto.store.stderr)) },
       stdall: { get: once(() => bufArrJoin(dto.store.stdall)) },

src/goods.ts

@@ -194,7 +194,7 @@ export async function spinner<T>(
   title: string | (() => T),
   callback?: () => T
 ): Promise<T> {
-  if (typeof title == 'function') {
+  if (typeof title === 'function') {
     callback = title
     title = ''
   }

test/core.test.js

@@ -253,15 +253,17 @@ describe('core', () => {
         assert.equal(o1.exitCode, 1)
         assert.match(o1.message, /exit code: 1/)
 
+        const err = new Error('BrokenSpawn')
         const o2 = await $({
           nothrow: true,
           spawn() {
-            throw new Error('BrokenSpawn')
+            throw err
           },
         })`echo foo`
         assert.equal(o2.ok, false)
         assert.equal(o2.exitCode, null)
         assert.match(o2.message, /BrokenSpawn/)
+        assert.equal(o2.cause, err)
       })
 
       test('handles `input` option', async () => {