js-on-sx: Array.prototype includes/find/some/every/reverse + Object fallbacks

Array: includes, find, findIndex, some, every, reverse via
tail-recursive helpers.

Object: hasOwnProperty, isPrototypeOf, propertyIsEnumerable,
toString, valueOf, toLocaleString fallback in js-invoke-method
when js-get-prop returns undefined. Lets o.hasOwnProperty('k')
work on plain dicts.

376/378 unit (+13), 148/148 slice unchanged.

lib/js/runtime.sx

@@ -96,10 +96,45 @@
         (let
           ((m (js-get-prop recv key)))
           (cond
-            ((js-undefined? m)
+            ((not (js-undefined? m)) (js-call-with-this recv m args))
+            ((and (dict? recv) (js-object-builtin-method? key))
+              (js-invoke-object-method recv key args))
+            (else
               (error
-                (str "TypeError: " (js-to-string key) " is not a function")))
+                (str "TypeError: " (js-to-string key) " is not a function")))))))))
-            (else (js-call-with-this recv m args))))))))
+
+(define
+  js-object-builtin-method?
+  (fn
+    (name)
+    (or
+      (= name "hasOwnProperty")
+      (= name "isPrototypeOf")
+      (= name "propertyIsEnumerable")
+      (= name "toString")
+      (= name "valueOf")
+      (= name "toLocaleString"))))
+
+(define
+  js-invoke-object-method
+  (fn
+    (recv name args)
+    (cond
+      ((= name "hasOwnProperty")
+        (if
+          (= (len args) 0)
+          false
+          (contains? (keys recv) (js-to-string (nth args 0)))))
+      ((= name "isPrototypeOf") false)
+      ((= name "propertyIsEnumerable")
+        (if
+          (= (len args) 0)
+          false
+          (contains? (keys recv) (js-to-string (nth args 0)))))
+      ((= name "toString") "[object Object]")
+      ((= name "valueOf") recv)
+      ((= name "toLocaleString") "[object Object]")
+      (else js-undefined))))
 
 (define js-upper-case (fn (s) (js-case-loop s 0 "" true)))
 
@@ -179,6 +214,13 @@
       ((= code 122) "z")
       (else ""))))
 
+;; parse a decimal number from a trimmed non-empty string.
+;;   s      — source
+;;   i      — cursor
+;;   acc    — integer part so far (or total for decimals)
+;;   sign   — 1 or -1
+;;   frac?  — are we past the decimal point
+;;   fdiv   — divisor used to scale fraction digits (only if frac?)
 (define
   js-invoke-method-dyn
   (fn (recv key args) (js-invoke-method recv key args)))
@@ -192,13 +234,6 @@
         (error "TypeError: undefined is not a function"))
       (else (js-call-with-this :js-undefined fn-val args)))))
 
-;; parse a decimal number from a trimmed non-empty string.
-;;   s      — source
-;;   i      — cursor
-;;   acc    — integer part so far (or total for decimals)
-;;   sign   — 1 or -1
-;;   frac?  — are we past the decimal point
-;;   fdiv   — divisor used to scale fraction digits (only if frac?)
 (define
   js-new-call
   (fn
@@ -214,6 +249,8 @@
             ret
             obj))))))
 
+;; ── String coercion (ToString) ────────────────────────────────────
+
 (define
   js-instanceof
   (fn
@@ -242,8 +279,9 @@
             ((not (= (type-of p) "dict")) false)
             (else (js-instanceof-walk p proto))))))))
 
-;; ── String coercion (ToString) ────────────────────────────────────
+;; ── Arithmetic (JS rules) ─────────────────────────────────────────
 
+;; JS `+`: if either operand is a string → string concat, else numeric.
 (define
   js-in
   (fn
@@ -262,9 +300,6 @@
       ((dict-has? obj "__proto__") (js-in-walk (get obj "__proto__") skey))
       (else false))))
 
-;; ── Arithmetic (JS rules) ─────────────────────────────────────────
-
-;; JS `+`: if either operand is a string → string concat, else numeric.
 (define
   Error
   (fn
@@ -363,11 +398,14 @@
       ((t (type-of v)))
       (or (= t "lambda") (= t "function") (= t "component")))))
 
+;; Bitwise + logical-not
 (define __js_proto_table__ (dict))
 
 (define __js_next_id__ (dict))
 
-;; Bitwise + logical-not
+;; ── Equality ──────────────────────────────────────────────────────
+
+;; Strict equality (===): no coercion; js-undefined matches js-undefined.
 (dict-set! __js_next_id__ "n" 0)
 
 (define
@@ -381,9 +419,9 @@
         (else
           (let ((p (dict))) (begin (dict-set! __js_proto_table__ id p) p)))))))
 
-;; ── Equality ──────────────────────────────────────────────────────
+;; Abstract equality (==): type coercion rules.
-
+;; Simplified: number↔string coerce both to number; null == undefined;
-;; Strict equality (===): no coercion; js-undefined matches js-undefined.
+;; everything else falls back to strict equality.
 (define
   js-reset-ctor-proto!
   (fn
@@ -398,9 +436,11 @@
     (ctor proto)
     (let ((id (js-ctor-id ctor))) (dict-set! __js_proto_table__ id proto))))
 
-;; Abstract equality (==): type coercion rules.
+;; ── Relational comparisons ────────────────────────────────────────
-;; Simplified: number↔string coerce both to number; null == undefined;
+
-;; everything else falls back to strict equality.
+;; Abstract relational comparison from ES5.
+;; Numbers compare numerically; two strings compare lexicographically;
+;; mixed types coerce both to numbers.
 (define
   js-ctor-id
   (fn
@@ -424,11 +464,6 @@
       ((= (type-of v) "native-fn") "function")
       (else "object"))))
 
-;; ── Relational comparisons ────────────────────────────────────────
-
-;; Abstract relational comparison from ES5.
-;; Numbers compare numerically; two strings compare lexicographically;
-;; mixed types coerce both to numbers.
 (define
   js-to-boolean
   (fn
@@ -470,12 +505,6 @@
         ((= trimmed "") 0)
         (else (js-parse-decimal trimmed 0 0 1 false 0))))))
 
-(define js-trim (fn (s) (js-trim-left (js-trim-right s))))
-
-(define
-  js-trim-left
-  (fn (s) (let ((n (len s))) (js-trim-left-at s n 0))))
-
 ;; ── Property access ───────────────────────────────────────────────
 
 ;; obj[key] or obj.key in JS. Handles:
@@ -483,6 +512,12 @@
 ;;   • lists indexed by number (incl. .length)
 ;;   • strings indexed by number (incl. .length)
 ;; Returns js-undefined if the key is absent.
+(define js-trim (fn (s) (js-trim-left (js-trim-right s))))
+
+(define
+  js-trim-left
+  (fn (s) (let ((n (len s))) (js-trim-left-at s n 0))))
+
 (define
   js-trim-left-at
   (fn
@@ -492,10 +527,15 @@
       ((js-is-space? (char-at s i)) (js-trim-left-at s n (+ i 1)))
       (else (substr s i n)))))
 
+;; Setter — mutates the dict. Returns the new value (JS assignment yields rhs).
 (define
   js-trim-right
   (fn (s) (let ((n (len s))) (js-trim-right-at s n))))
 
+;; ── Short-circuit logical ops ─────────────────────────────────────
+
+;; `a && b` in JS: if a is truthy return b else return a. The thunk
+;; form defers evaluation of b — the transpiler passes (fn () b).
 (define
   js-trim-right-at
   (fn
@@ -505,15 +545,13 @@
       ((js-is-space? (char-at s (- n 1))) (js-trim-right-at s (- n 1)))
       (else (substr s 0 n)))))
 
-;; Setter — mutates the dict. Returns the new value (JS assignment yields rhs).
 (define
   js-is-space?
   (fn (c) (or (= c " ") (= c "\t") (= c "\n") (= c "\r"))))
 
-;; ── Short-circuit logical ops ─────────────────────────────────────
+;; ── console.log ───────────────────────────────────────────────────
 
-;; `a && b` in JS: if a is truthy return b else return a. The thunk
+;; Trivial bridge. `log-info` is available on OCaml; fall back to print.
-;; form defers evaluation of b — the transpiler passes (fn () b).
 (define
   js-parse-decimal
   (fn
@@ -564,9 +602,8 @@
         (= c "8")
         (= c "9")))))
 
-;; ── console.log ───────────────────────────────────────────────────
+;; ── Math object ───────────────────────────────────────────────────
 
-;; Trivial bridge. `log-info` is available on OCaml; fall back to print.
 (define
   js-digit-val
   (fn
@@ -583,7 +620,6 @@
       ((= c "8") 8)
       ((= c "9") 9)
       (else 0))))
-
 (define
   js-to-string
   (fn
@@ -596,9 +632,6 @@
       ((= (type-of v) "string") v)
       ((= (type-of v) "number") (js-number-to-string v))
       (else (str v)))))
-
-;; ── Math object ───────────────────────────────────────────────────
-
 (define
   js-template-concat
   (fn (&rest parts) (js-template-concat-loop parts 0 "")))
@@ -624,16 +657,18 @@
       (else (+ (js-to-number a) (js-to-number b))))))
 (define js-sub (fn (a b) (- (js-to-number a) (js-to-number b))))
 (define js-mul (fn (a b) (* (js-to-number a) (js-to-number b))))
-(define js-div (fn (a b) (/ (js-to-number a) (js-to-number b))))
+(define js-div (fn (a b) (/ (js-to-number a) (js-to-number b))))   ; deterministic placeholder for tests
-(define js-mod (fn (a b) (mod (js-to-number a) (js-to-number b))))
-(define js-pow (fn (a b) (pow (js-to-number a) (js-to-number b))))   ; deterministic placeholder for tests
 
-(define js-neg (fn (a) (- 0 (js-to-number a))))
+(define js-mod (fn (a b) (mod (js-to-number a) (js-to-number b))))
 
 ;; The global object — lookup table for JS names that aren't in the
 ;; SX env. Transpiled idents look up locally first; globals here are a
 ;; fallback, but most slice programs reference `console`, `Math`,
 ;; `undefined` as plain symbols, which we bind as defines above.
+(define js-pow (fn (a b) (pow (js-to-number a) (js-to-number b))))
+
+(define js-neg (fn (a) (- 0 (js-to-number a))))
+
 (define js-pos (fn (a) (js-to-number a)))
 
 (define js-not (fn (a) (not (js-to-boolean a))))
@@ -762,6 +797,19 @@
                 (error "Reduce of empty array with no initial value")
                 (js-list-reduce-loop (nth args 0) (nth arr 0) arr 1)))
             (else (js-list-reduce-loop (nth args 0) (nth args 1) arr 0)))))
+      ((= name "includes")
+        (fn
+          (&rest args)
+          (if
+            (= (len args) 0)
+            false
+            (>= (js-list-index-of arr (nth args 0) 0) 0))))
+      ((= name "find") (fn (f) (js-list-find-loop f arr 0)))
+      ((= name "findIndex") (fn (f) (js-list-find-index-loop f arr 0)))
+      ((= name "some") (fn (f) (js-list-some-loop f arr 0)))
+      ((= name "every") (fn (f) (js-list-every-loop f arr 0)))
+      ((= name "reverse")
+        (fn () (js-list-reverse-loop arr (- (len arr) 1) (list))))
       (else js-undefined))))
 
 (define pop-last! (fn (lst) nil))
@@ -885,6 +933,53 @@
       ((>= i (len arr)) acc)
       (else (js-list-reduce-loop f (f acc (nth arr i)) arr (+ i 1))))))
 
+(define
+  js-list-find-loop
+  (fn
+    (f arr i)
+    (cond
+      ((>= i (len arr)) js-undefined)
+      ((js-to-boolean (f (nth arr i))) (nth arr i))
+      (else (js-list-find-loop f arr (+ i 1))))))
+
+(define
+  js-list-find-index-loop
+  (fn
+    (f arr i)
+    (cond
+      ((>= i (len arr)) -1)
+      ((js-to-boolean (f (nth arr i))) i)
+      (else (js-list-find-index-loop f arr (+ i 1))))))
+
+(define
+  js-list-some-loop
+  (fn
+    (f arr i)
+    (cond
+      ((>= i (len arr)) false)
+      ((js-to-boolean (f (nth arr i))) true)
+      (else (js-list-some-loop f arr (+ i 1))))))
+
+(define
+  js-list-every-loop
+  (fn
+    (f arr i)
+    (cond
+      ((>= i (len arr)) true)
+      ((not (js-to-boolean (f (nth arr i)))) false)
+      (else (js-list-every-loop f arr (+ i 1))))))
+
+(define
+  js-list-reverse-loop
+  (fn
+    (arr i acc)
+    (cond
+      ((< i 0) acc)
+      (else
+        (begin
+          (append! acc (nth arr i))
+          (js-list-reverse-loop arr (- i 1) acc))))))
+
 (define
   js-string-repeat
   (fn
@@ -1118,6 +1213,12 @@
             ((= key "filter") (js-array-method obj "filter"))
             ((= key "forEach") (js-array-method obj "forEach"))
             ((= key "reduce") (js-array-method obj "reduce"))
+            ((= key "includes") (js-array-method obj "includes"))
+            ((= key "find") (js-array-method obj "find"))
+            ((= key "findIndex") (js-array-method obj "findIndex"))
+            ((= key "some") (js-array-method obj "some"))
+            ((= key "every") (js-array-method obj "every"))
+            ((= key "reverse") (js-array-method obj "reverse"))
             (else js-undefined)))
         ((= (type-of obj) "string")
           (cond

lib/js/test.sh

@@ -951,6 +951,36 @@ cat > "$TMPFILE" << 'EPOCHS'
 (epoch 1605)
 (eval "(js-eval \"var r=0; switch(1){case 1: r=10; case 2: r=20; break;} r\")")
 
+;; ── Phase 11.array: more Array.prototype ────────────────────────
+(epoch 1700)
+(eval "(js-eval \"[1,2,3].includes(2)\")")
+(epoch 1701)
+(eval "(js-eval \"[1,2,3].includes(5)\")")
+(epoch 1702)
+(eval "(js-eval \"[1,2,3].find((x)=>x>1)\")")
+(epoch 1703)
+(eval "(js-eval \"[1,2,3].findIndex((x)=>x>1)\")")
+(epoch 1704)
+(eval "(js-eval \"[1,2,3].some((x)=>x>2)\")")
+(epoch 1705)
+(eval "(js-eval \"[1,2,3].some((x)=>x>5)\")")
+(epoch 1706)
+(eval "(js-eval \"[1,2,3].every((x)=>x>0)\")")
+(epoch 1707)
+(eval "(js-eval \"[1,2,3].every((x)=>x>2)\")")
+(epoch 1708)
+(eval "(js-eval \"[1,2,3].reverse().join(',')\")")
+
+;; ── Phase 11.objmethod: hasOwnProperty + toString ───────────────
+(epoch 1800)
+(eval "(js-eval \"var o = {x:1}; o.hasOwnProperty('x')\")")
+(epoch 1801)
+(eval "(js-eval \"var o = {x:1}; o.hasOwnProperty('y')\")")
+(epoch 1802)
+(eval "(js-eval \"({}).toString()\")")
+(epoch 1803)
+(eval "(js-eval \"({x:1}).valueOf().x\")")
+
 EPOCHS
 
 OUTPUT=$(timeout 180 "$SX_SERVER" < "$TMPFILE" 2>/dev/null)
@@ -1458,6 +1488,23 @@ check 1603 "switch fallthrough stops on break" '12'
 check 1604 "switch on string"              '"yes"'
 check 1605 "switch fallthrough chains"     '20'
 
+# ── Phase 11.array: more Array.prototype ────────────────────────
+check 1700 "Array.includes yes"            'true'
+check 1701 "Array.includes no"             'false'
+check 1702 "Array.find"                    '2'
+check 1703 "Array.findIndex"               '1'
+check 1704 "Array.some yes"                'true'
+check 1705 "Array.some no"                 'false'
+check 1706 "Array.every yes"               'true'
+check 1707 "Array.every no"                'false'
+check 1708 "Array.reverse"                 '"3,2,1"'
+
+# ── Phase 11.objmethod: hasOwnProperty ──────────────────────────
+check 1800 "hasOwnProperty yes"            'true'
+check 1801 "hasOwnProperty no"             'false'
+check 1802 "({}).toString()"               '"[object Object]"'
+check 1803 "obj.valueOf().x"               '1'
+
 TOTAL=$((PASS + FAIL))
 if [ $FAIL -eq 0 ]; then
   echo "✓ $PASS/$TOTAL JS-on-SX tests passed"

plans/js-on-sx.md

@@ -183,6 +183,8 @@ Append-only record of completed iterations. Loop writes one line per iteration:
 
 - 2026-04-23 — **switch / case / default.** Parser: new `jp-parse-switch-stmt` (expect `switch (expr) { cases }`), `jp-parse-switch-cases` (walks clauses: `case val:`, `default:`), `jp-parse-switch-body` (collects stmts until next `case`/`default`/`}`). AST: `(js-switch discr (("case" val body-stmts) ("default" nil body-stmts) ...))`. Transpile: wraps body in `(call/cc (fn (__break__) (let ((__discr__ …) (__matched__ false)) …)))`. Each case clause becomes `(when (or __matched__ (js-strict-eq __discr__ val)) (set! __matched__ true) body-stmts)` — implements JS fall-through naturally (once a case matches, all following cases' `when` fires via `__matched__`). Default is a separate `(when (not __matched__) default-body)` appended at the end. `break` inside a case body already transpiles to `(__break__ nil)` and jumps out via the `call/cc`. 6 new unit tests (match, no-match default, fall-through stops on break, string discriminant, empty-body fall-through chain), **363/365** (357→+6). Conformance unchanged.
 
+- 2026-04-23 — **More Array.prototype + Object fallbacks (`hasOwnProperty` etc).** Array: `includes`, `find`, `findIndex`, `some`, `every`, `reverse` (in `js-array-method` dispatch + `js-get-prop` list-branch keys). Helpers: `js-list-find-loop / -find-index-loop / -some-loop / -every-loop / -reverse-loop` all tail-recursive, no `while` because SX doesn't have one. Object fallbacks: `js-invoke-method` now falls back to `js-invoke-object-method` for dicts when js-get-prop returns undefined AND the method name is in the builtin set (`hasOwnProperty`, `isPrototypeOf`, `propertyIsEnumerable`, `toString`, `valueOf`, `toLocaleString`). `hasOwnProperty` checks `(contains? (keys recv) (js-to-string k))`. This lets `o.hasOwnProperty('x')` work on plain dicts without having to install an Object.prototype. 13 new tests, **376/378** (363→+13). Conformance unchanged.
+
 ## Phase 3-5 gotchas
 
 Worth remembering for later phases: