js-on-sx: arrays accept numeric-string property keys

JS arrays must treat string indices that look like numbers ("0",
"42") as the corresponding integer slot. js-get-prop and js-list-set!
only handled numeric key, falling through to undefined / no-op for
string keys. Added a (and (string-typed key) (numeric? key)) clause
that converts via js-string-to-number and recurses with the integer
key. built-ins/Array: 13/45 → 14/45. conformance.sh: 148/148.

lib/js/runtime.sx

@@ -2639,6 +2639,13 @@
                 (and (>= key 0) (< key (len obj)))
                 (nth obj (js-num-to-int key))
                 js-undefined))
+            ((and (= (type-of key) "string") (js-is-numeric-string? key))
+              (let
+                ((idx (js-num-to-int (js-string-to-number key))))
+                (if
+                  (and (>= idx 0) (< idx (len obj)))
+                  (nth obj idx)
+                  js-undefined)))
             ((= key "push") (js-array-method obj "push"))
             ((= key "pop") (js-array-method obj "pop"))
             ((= key "shift") (js-array-method obj "shift"))
@@ -2791,6 +2798,8 @@
               ((< i n) (set-nth! lst i val))
               ((= i n) (append! lst val))
               (else (do (js-pad-list! lst n i) (append! lst val))))))
+        ((and (= (type-of key) "string") (js-is-numeric-string? key))
+          (js-list-set! lst (js-string-to-number key) val))
         ((= key "length") nil)
         (else nil))))
   (define

lib/js/test262-scoreboard.json

@@ -1,37 +1,41 @@
 {
   "totals": {
-    "pass": 77,
-    "fail": 15,
-    "skip": 1,
-    "timeout": 7,
-    "total": 100,
-    "runnable": 99,
-    "pass_rate": 77.8
+    "pass": 14,
+    "fail": 25,
+    "skip": 5,
+    "timeout": 6,
+    "total": 50,
+    "runnable": 45,
+    "pass_rate": 31.1
   },
   "categories": [
     {
-      "category": "built-ins/String",
-      "total": 100,
-      "pass": 77,
-      "fail": 15,
-      "skip": 1,
-      "timeout": 7,
-      "pass_rate": 77.8,
+      "category": "built-ins/Array",
+      "total": 50,
+      "pass": 14,
+      "fail": 25,
+      "skip": 5,
+      "timeout": 6,
+      "pass_rate": 31.1,
       "top_failures": [
         [
           "Test262Error (assertion failed)",
-          13
+          20
         ],
         [
           "Timeout",
-          7
+          6
+        ],
+        [
+          "TypeError: not a function",
+          2
         ],
         [
           "ReferenceError (undefined symbol)",
-          1
+          2
         ],
         [
-          "SyntaxError (parse/unsupported syntax)",
+          "Unhandled: Not callable: {:2 43 :1 42 :0 41 :length 3}\\",
           1
         ]
       ]
@@ -40,22 +44,26 @@
   "top_failure_modes": [
     [
       "Test262Error (assertion failed)",
-      13
+      20
     ],
     [
       "Timeout",
-      7
+      6
+    ],
+    [
+      "TypeError: not a function",
+      2
     ],
     [
       "ReferenceError (undefined symbol)",
-      1
+      2
     ],
     [
-      "SyntaxError (parse/unsupported syntax)",
+      "Unhandled: Not callable: {:2 43 :1 42 :0 41 :length 3}\\",
       1
     ]
   ],
   "pinned_commit": "d5e73fc8d2c663554fb72e2380a8c2bc1a318a33",
-  "elapsed_seconds": 486.8,
+  "elapsed_seconds": 132.0,
   "workers": 1
 }

lib/js/test262-scoreboard.md

@@ -1,28 +1,30 @@
 # test262 scoreboard
 
 Pinned commit: `d5e73fc8d2c663554fb72e2380a8c2bc1a318a33`
-Wall time: 486.8s
+Wall time: 132.0s
 
-**Total:** 77/99 runnable passed (77.8%). Raw: pass=77 fail=15 skip=1 timeout=7 total=100.
+**Total:** 14/45 runnable passed (31.1%). Raw: pass=14 fail=25 skip=5 timeout=6 total=50.
 
 ## Top failure modes
 
-- **13x** Test262Error (assertion failed)
-- **7x** Timeout
-- **1x** ReferenceError (undefined symbol)
-- **1x** SyntaxError (parse/unsupported syntax)
+- **20x** Test262Error (assertion failed)
+- **6x** Timeout
+- **2x** TypeError: not a function
+- **2x** ReferenceError (undefined symbol)
+- **1x** Unhandled: Not callable: {:2 43 :1 42 :0 41 :length 3}\
 
 ## Categories (worst pass-rate first, min 10 runnable)
 
 | Category | Pass | Fail | Skip | Timeout | Total | Pass % |
 |---|---:|---:|---:|---:|---:|---:|
-| built-ins/String | 77 | 15 | 1 | 7 | 100 | 77.8% |
+| built-ins/Array | 14 | 25 | 5 | 6 | 50 | 31.1% |
 
 ## Per-category top failures (min 10 runnable, worst first)
 
-### built-ins/String  (77/99 — 77.8%)
+### built-ins/Array  (14/45 — 31.1%)
 
-- **13x** Test262Error (assertion failed)
-- **7x** Timeout
-- **1x** ReferenceError (undefined symbol)
-- **1x** SyntaxError (parse/unsupported syntax)
+- **20x** Test262Error (assertion failed)
+- **6x** Timeout
+- **2x** TypeError: not a function
+- **2x** ReferenceError (undefined symbol)
+- **1x** Unhandled: Not callable: {:2 43 :1 42 :0 41 :length 3}\

plans/js-on-sx.md

@@ -158,6 +158,8 @@ Each item: implement → tests → update progress. Mark `[x]` when tests green.
 
 Append-only record of completed iterations. Loop writes one line per iteration: date, what was done, test count delta.
 
+- 2026-05-08 — **Arrays accept numeric-string property keys (`arr["0"]`).** JS arrays must treat string indices that look like numbers (`"0"`, `"42"`) as the corresponding integer slot — `var x = []; x["0"] = 5; x[0] === 5`. `js-get-prop` and `js-list-set!` only handled numeric `key`, falling through to `js-undefined` / no-op for string keys. Added a clause that converts numeric strings via `js-string-to-number` and recurses with the integer key. built-ins/Array: 13/45 → 14/45. conformance.sh: 148/148.
+
 - 2026-05-07 — **JS top-level `var` no longer pollutes SX global env; call args use `js-args` to avoid `list` shadow.** `var list = X` transpiled to `(define list X)` at top level, which permanently rebound the SX `list` primitive. Then any later code (including the runtime itself) calling `(list ...)` got "Not callable: <X>". Two-part fix: (1) wrap the whole transpiled program in `(let () ...)` in `js-eval` so `define`s scope to the eval session and don't leak; (2) rename the call-args constructor in `js-transpile-args` from `list` to `js-args` (a new variadic alias) so even within the eval's own scope, JS variables named `list` don't shadow argument-list construction. Array-literal transpile keeps `list` (lists must be mutable). built-ins/Object: 41/50 → 42/50; Array.from on array-likes now works. conformance.sh: 148/148.
 
 - 2026-05-07 — **`Object.__callable__` returns `this` for `new Object()` no-args path.** `js-new-call Object` had `obj.__proto__ = Object.prototype` already set, but then Object.__callable__ returned a fresh `(dict)`, which `js-new-call`'s "use returned dict over `obj`" rule honoured — losing the proto. Added a `is-new` check (`this.__proto__ === Object.prototype`) and return `this` instead of a fresh dict when invoked as a constructor with no/null args. Now `new Object().__proto__ === Object.prototype`, `Object.prototype.isPrototypeOf(new Object())`, and `.constructor === Object` all work. built-ins/Object: 37/50 → 41/50. conformance.sh: 148/148.