From 98b5d5754be86e7ffc6b0470be14f5f8677b3857 Mon Sep 17 00:00:00 2001
From: Anton Golub <antongolub@antongolub.com>
Date: Sun, 23 Feb 2025 15:43:14 +0300
Subject: [PATCH] feat: define `Symbol.toPrimitive`

---
 .size-limit.json  |  4 ++--
 src/core.ts       | 12 ++++++++++--
 test/core.test.js | 10 ++++++++++
 3 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/.size-limit.json b/.size-limit.json
index 2f6ce22ddd..5772945e1a 100644
--- a/.size-limit.json
+++ b/.size-limit.json
@@ -9,14 +9,14 @@
   {
     "name": "zx/index",
     "path": "build/*.{js,cjs}",
-    "limit": "811 kB",
+    "limit": "812 kB",
     "brotli": false,
     "gzip": false
   },
   {
     "name": "dts libdefs",
     "path": "build/*.d.ts",
-    "limit": "38.7 kB",
+    "limit": "39 kB",
     "brotli": false,
     "gzip": false
   },
diff --git a/src/core.ts b/src/core.ts
index bf85e68b57..4f56666469 100644
--- a/src/core.ts
+++ b/src/core.ts
@@ -485,10 +485,14 @@ export class ProcessPromise extends Promise<ProcessOutput> {
     return this._stage
   }
 
-  get [Symbol.toStringTag]() {
+  get [Symbol.toStringTag](): string {
     return 'ProcessPromise'
   }
 
+  [Symbol.toPrimitive](): string {
+    return this.toString()
+  }
+
   // Configurators
   stdio(
     stdin: IOType,
@@ -728,10 +732,14 @@ export class ProcessOutput extends Error {
     return this._dto.duration
   }
 
-  get [Symbol.toStringTag]() {
+  get [Symbol.toStringTag](): string {
     return 'ProcessOutput'
   }
 
+  [Symbol.toPrimitive](): string {
+    return this.valueOf()
+  }
+
   toString(): string {
     return this.stdall
   }
diff --git a/test/core.test.js b/test/core.test.js
index fee4148dcb..1146998e49 100644
--- a/test/core.test.js
+++ b/test/core.test.js
@@ -423,6 +423,9 @@ describe('core', () => {
       assert.ok(p.signal instanceof AbortSignal)
       assert.equal(p.output, null)
       assert.equal(Object.prototype.toString.call(p), '[object ProcessPromise]')
+      assert.equal('' + p, '[object ProcessPromise]')
+      assert.equal(`${p}`, '[object ProcessPromise]')
+      assert.equal(+p, NaN)
 
       await p
       assert.ok(p.output instanceof ProcessOutput)
@@ -1103,6 +1106,13 @@ describe('core', () => {
       assert.equal(Object.prototype.toString.call(o), '[object ProcessOutput]')
     })
 
+    test('[Symbol.toPrimitive]', () => {
+      const o = new ProcessOutput(-1, 'SIGTERM', '', '', 'foo\n', 'msg', 20)
+      assert.equal('' + o, 'foo')
+      assert.equal(`${o}`, 'foo')
+      assert.equal(+o, NaN)
+    })
+
     test('toString()', async () => {
       const o = new ProcessOutput(null, null, '', '', 'foo\n')
       assert.equal(o.toString(), 'foo\n')