feat: make ProcessOutput iterable

closes #1053
closes #1027

relates #1088
relates #984

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 kB",
+    "limit": "77.5 kB",
     "brotli": false,
     "gzip": false
   },
@@ -30,7 +30,7 @@
   {
     "name": "all",
     "path": "build/*",
-    "limit": "849 kB",
+    "limit": "850 kB",
     "brotli": false,
     "gzip": false
   }

src/core.ts

@@ -758,13 +758,26 @@ export class ProcessOutput extends Error {
   }
 
   lines(): string[] {
-    return this.valueOf().split(/\r?\n/)
+    return [...this]
   }
 
   valueOf(): string {
     return this.stdall.trim()
   }
 
+  *[Symbol.iterator](): Iterator<string> {
+    let buffer = ''
+
+    for (const chunk of this._dto.store.stdall) {
+      buffer += chunk.toString()
+      const lines = buffer.split(/\r?\n/)
+      buffer = lines.pop() ?? ''
+      yield* lines
+    }
+
+    if (buffer) yield buffer
+  }
+
   static getExitMessage = formatExitMessage
 
   static getErrorMessage = formatErrorMessage;

test/core.test.js

@@ -1162,6 +1162,21 @@ describe('core', () => {
       globalThis.Blob = Blob
     })
 
+    test('[Symbol.Iterator]', () => {
+      const o = new ProcessOutput({
+        store: {
+          stdall: ['foo\nba', 'r\nbaz'],
+        },
+      })
+      const lines = []
+      const expected = ['foo', 'bar', 'baz']
+      for (const line of o) {
+        lines.push(line)
+      }
+      assert.deepEqual(lines, expected)
+      assert.deepEqual(o.lines(), expected)
+    })
+
     describe('static', () => {
       test('getExitMessage()', () => {
         assert.match(

test/smoke/node.test.mjs

@@ -19,6 +19,7 @@ import 'zx/globals'
   {
     const p = await $`echo foo`
     assert.match(p.stdout, /foo/)
+    assert.deepEqual(p.lines(), ['foo'])
   }
 
   // captures err stack