Expand JSON.stringify error coverage

[frostney]

Summary

• expand JSON.stringify coverage for circular references, toJSON, thrown errors, invalid replacers/space, symbols, functions, deep nesting, and sparse arrays
• align the runtime JSON serializer with the new edge-case expectations, including cycle detection and toJSON() handling
• document the supported JSON.stringify special cases in docs/built-ins.md

Testing

• ./build.pas clean loader
• ./build.pas testrunner
• ./build/TestRunner tests/built-ins/JSON/stringify.js --no-progress
• ./build/TestRunner tests --no-progress

Closes #122.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: fff62131-0d60-407b-be27-8c46267f9469

📥 Commits

Reviewing files that changed from the base of the PR and between 0f48261 and 8e56ed4.

📒 Files selected for processing (4)

• docs/built-ins.md
• tests/built-ins/JSON/stringify.js
• units/Goccia.Builtins.JSON.pas
• units/Goccia.JSON.pas

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch feature/json-stringify-error-tests

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[github-actions]

Benchmark Results

263 benchmarks

Interpreted: 🔴 19 regressed · 244 unchanged · avg -2.5%
Bytecode: 🟢 1 improved · 🔴 149 regressed · 113 unchanged · avg -7.7%

arraybuffer.js — Interp: 14 unch. · avg -0.0% · Bytecode: 🔴 8, 6 unch. · avg -8.2%

Benchmark	Interpreted	Δ	Bytecode	Δ
create ArrayBuffer(0)	462,301 → 450,997	-2.4%	561,933 → 498,852	🔴 -11.2%
create ArrayBuffer(64)	440,456 → 434,094	-1.4%	532,568 → 479,761	🔴 -9.9%
create ArrayBuffer(1024)	346,984 → 337,305	-2.8%	422,269 → 372,617	🔴 -11.8%
create ArrayBuffer(8192)	153,321 → 149,248	-2.7%	182,033 → 162,110	🔴 -10.9%
slice full buffer (64 bytes)	505,311 → 518,779	+2.7%	661,856 → 607,240	🔴 -8.3%
slice half buffer (512 of 1024 bytes)	433,786 → 445,944	+2.8%	566,871 → 524,840	🔴 -7.4%
slice with negative indices	428,778 → 419,021	-2.3%	606,673 → 567,151	-6.5%
slice empty range	490,378 → 498,040	+1.6%	648,800 → 604,311	-6.9%
byteLength access	1,341,940 → 1,388,175	+3.4%	1,707,660 → 1,602,486	-6.2%
Symbol.toStringTag access	1,040,240 → 1,045,302	+0.5%	1,127,606 → 1,069,995	-5.1%
ArrayBuffer.isView	748,768 → 765,223	+2.2%	922,309 → 874,509	-5.2%
clone ArrayBuffer(64)	418,819 → 412,728	-1.5%	519,553 → 485,626	-6.5%
clone ArrayBuffer(1024)	326,928 → 324,504	-0.7%	412,596 → 366,905	🔴 -11.1%
clone ArrayBuffer inside object	267,728 → 267,781	+0.0%	321,236 → 297,468	🔴 -7.4%

arrays.js — Interp: 19 unch. · avg +0.2% · Bytecode: 🔴 18, 1 unch. · avg -10.1%

Benchmark	Interpreted	Δ	Bytecode	Δ
Array.from length 100	13,211 → 12,991	-1.7%	15,612 → 14,189	🔴 -9.1%
Array.from 10 elements	221,335 → 220,731	-0.3%	266,653 → 238,307	🔴 -10.6%
Array.of 10 elements	278,403 → 280,189	+0.6%	334,835 → 310,173	🔴 -7.4%
spread into new array	325,442 → 323,766	-0.5%	207,924 → 190,647	🔴 -8.3%
map over 50 elements	24,521 → 24,540	+0.1%	29,099 → 26,310	🔴 -9.6%
filter over 50 elements	22,837 → 22,639	-0.9%	26,651 → 23,500	🔴 -11.8%
reduce sum 50 elements	25,133 → 26,058	+3.7%	20,938 → 19,551	-6.6%
forEach over 50 elements	22,344 → 22,938	+2.7%	30,770 → 28,115	🔴 -8.6%
find in 50 elements	32,076 → 31,762	-1.0%	33,071 → 30,608	🔴 -7.4%
sort 20 elements	12,577 → 12,471	-0.8%	14,743 → 10,508	🔴 -28.7%
flat nested array	116,883 → 113,098	-3.2%	139,711 → 127,932	🔴 -8.4%
flatMap	72,575 → 70,622	-2.7%	89,721 → 81,607	🔴 -9.0%
map inside map (5x5)	20,211 → 20,273	+0.3%	24,820 → 22,303	🔴 -10.1%
filter inside map (5x10)	15,637 → 15,643	+0.0%	18,526 → 16,490	🔴 -11.0%
reduce inside map (5x10)	18,592 → 19,025	+2.3%	17,661 → 16,194	🔴 -8.3%
forEach inside forEach (5x10)	16,309 → 16,485	+1.1%	18,508 → 17,093	🔴 -7.6%
find inside some (10x10)	13,157 → 13,276	+0.9%	14,313 → 13,090	🔴 -8.5%
map+filter chain nested (5x20)	5,113 → 5,146	+0.6%	6,030 → 5,393	🔴 -10.5%
reduce flatten (10x5)	37,510 → 38,679	+3.1%	19,216 → 17,361	🔴 -9.7%

async-await.js — Interp: 6 unch. · avg +2.0% · Bytecode: 🔴 5, 1 unch. · avg -8.5%

Benchmark	Interpreted	Δ	Bytecode	Δ
single await	376,248 → 385,744	+2.5%	449,506 → 404,864	🔴 -9.9%
multiple awaits	169,125 → 172,041	+1.7%	196,626 → 175,751	🔴 -10.6%
await non-Promise value	839,801 → 860,108	+2.4%	1,170,424 → 1,111,299	-5.1%
await with try/catch	365,461 → 369,191	+1.0%	442,618 → 404,269	🔴 -8.7%
await Promise.all	51,437 → 52,145	+1.4%	56,604 → 51,632	🔴 -8.8%
nested async function call	192,686 → 198,070	+2.8%	251,322 → 231,530	🔴 -7.9%

classes.js — Interp: 31 unch. · avg -0.5% · Bytecode: 🔴 20, 11 unch. · avg -7.7%

Benchmark	Interpreted	Δ	Bytecode	Δ
simple class new	139,123 → 140,718	+1.1%	218,718 → 203,820	-6.8%
class with defaults	109,944 → 113,996	+3.7%	152,567 → 142,804	-6.4%
50 instances via Array.from	5,605 → 5,684	+1.4%	8,695 → 7,895	🔴 -9.2%
instance method call	71,250 → 71,319	+0.1%	101,066 → 93,692	🔴 -7.3%
static method call	114,857 → 112,953	-1.7%	204,737 → 187,309	🔴 -8.5%
single-level inheritance	56,323 → 55,659	-1.2%	81,626 → 74,546	🔴 -8.7%
two-level inheritance	48,059 → 47,976	-0.2%	65,083 → 60,414	🔴 -7.2%
private field access	71,986 → 70,907	-1.5%	105,517 → 95,811	🔴 -9.2%
private methods	80,242 → 78,384	-2.3%	112,797 → 101,585	🔴 -9.9%
getter/setter access	75,740 → 75,757	+0.0%	116,010 → 103,100	🔴 -11.1%
class decorator (identity)	92,910 → 92,996	+0.1%	111,923 → 102,520	🔴 -8.4%
class decorator (wrapping)	54,944 → 54,457	-0.9%	64,254 → 58,874	🔴 -8.4%
identity method decorator	65,686 → 64,916	-1.2%	95,462 → 84,530	🔴 -11.5%
wrapping method decorator	52,435 → 52,047	-0.7%	67,466 → 60,663	🔴 -10.1%
stacked method decorators (x3)	35,330 → 35,212	-0.3%	46,096 → 41,747	🔴 -9.4%
identity field decorator	70,749 → 70,558	-0.3%	83,722 → 74,394	🔴 -11.1%
field initializer decorator	60,119 → 59,986	-0.2%	74,897 → 72,023	-3.8%
getter decorator (identity)	64,634 → 66,094	+2.3%	83,188 → 71,868	🔴 -13.6%
setter decorator (identity)	54,490 → 54,816	+0.6%	66,805 → 64,189	-3.9%
static method decorator	70,276 → 70,121	-0.2%	86,064 → 77,326	🔴 -10.2%
static field decorator	82,409 → 81,464	-1.1%	88,736 → 86,285	-2.8%
private method decorator	53,462 → 52,364	-2.1%	86,450 → 70,328	🔴 -18.6%
private field decorator	59,070 → 58,277	-1.3%	61,133 → 62,300	+1.9%
plain auto-accessor (no decorator)	102,344 → 102,670	+0.3%	114,186 → 96,774	🔴 -15.2%
auto-accessor with decorator	54,906 → 54,680	-0.4%	60,890 → 54,278	🔴 -10.9%
decorator writing metadata	44,199 → 43,966	-0.5%	50,362 → 48,823	-3.1%
static getter read	128,456 → 125,900	-2.0%	164,267 → 164,494	+0.1%
static getter/setter pair	97,375 → 94,764	-2.7%	121,548 → 118,803	-2.3%
inherited static getter	76,376 → 74,615	-2.3%	97,881 → 94,489	-3.5%
inherited static setter	82,769 → 81,698	-1.3%	107,026 → 99,387	🔴 -7.1%
inherited static getter with this binding	69,885 → 70,374	+0.7%	88,082 → 87,160	-1.0%

closures.js — Interp: 11 unch. · avg -0.1% · Bytecode: 🔴 4, 7 unch. · avg -6.0%

Benchmark	Interpreted	Δ	Bytecode	Δ
closure over single variable	130,471 → 130,676	+0.2%	293,124 → 268,878	🔴 -8.3%
closure over multiple variables	117,723 → 119,483	+1.5%	199,855 → 192,502	-3.7%
nested closures	124,910 → 126,689	+1.4%	231,965 → 221,115	-4.7%
function as argument	93,359 → 93,265	-0.1%	260,549 → 246,752	-5.3%
function returning function	114,251 → 116,815	+2.2%	299,170 → 273,279	🔴 -8.7%
compose two functions	69,647 → 70,862	+1.7%	153,471 → 148,280	-3.4%
fn.call	153,328 → 147,396	-3.9%	227,917 → 227,252	-0.3%
fn.apply	109,258 → 108,421	-0.8%	162,416 → 155,342	-4.4%
fn.bind	143,722 → 141,690	-1.4%	296,462 → 277,286	-6.5%
recursive sum to 50	12,040 → 11,661	-3.1%	27,006 → 24,022	🔴 -11.0%
recursive tree traversal	20,191 → 20,316	+0.6%	38,526 → 34,825	🔴 -9.6%

collections.js — Interp: 12 unch. · avg +0.3% · Bytecode: 🔴 3, 9 unch. · avg -3.3%

Benchmark	Interpreted	Δ	Bytecode	Δ
add 50 elements	6,896 → 7,075	+2.6%	7,636 → 7,371	-3.5%
has lookup (50 elements)	88,299 → 90,630	+2.6%	101,197 → 99,717	-1.5%
delete elements	46,722 → 48,306	+3.4%	50,770 → 49,306	-2.9%
forEach iteration	15,813 → 15,387	-2.7%	16,727 → 15,479	🔴 -7.5%
spread to array	27,504 → 27,901	+1.4%	231,607 → 209,808	🔴 -9.4%
deduplicate array	36,425 → 37,639	+3.3%	73,505 → 71,334	-3.0%
set 50 entries	5,141 → 5,164	+0.4%	5,611 → 5,625	+0.3%
get lookup (50 entries)	87,122 → 86,150	-1.1%	92,049 → 91,545	-0.5%
has check	129,001 → 128,558	-0.3%	142,453 → 140,223	-1.6%
delete entries	45,965 → 45,540	-0.9%	46,961 → 47,003	+0.1%
forEach iteration	15,792 → 15,171	-3.9%	17,036 → 15,418	🔴 -9.5%
keys/values/entries	7,727 → 7,640	-1.1%	26,361 → 26,077	-1.1%

destructuring.js — Interp: 22 unch. · avg -1.7% · Bytecode: 🔴 13, 9 unch. · avg -8.4%

Benchmark	Interpreted	Δ	Bytecode	Δ
simple array destructuring	368,216 → 370,593	+0.6%	266,346 → 258,426	-3.0%
with rest element	246,548 → 238,519	-3.3%	231,235 → 199,032	🔴 -13.9%
with defaults	375,709 → 384,870	+2.4%	298,282 → 297,547	-0.2%
skip elements	388,488 → 394,191	+1.5%	324,583 → 278,188	🔴 -14.3%
nested array destructuring	168,552 → 166,032	-1.5%	91,714 → 85,954	-6.3%
swap variables	493,046 → 497,464	+0.9%	368,249 → 315,699	🔴 -14.3%
simple object destructuring	302,653 → 295,187	-2.5%	427,919 → 407,030	-4.9%
with defaults	336,230 → 335,977	-0.1%	574,994 → 549,507	-4.4%
with renaming	315,911 → 317,370	+0.5%	467,953 → 442,836	-5.4%
nested object destructuring	152,328 → 150,301	-1.3%	200,891 → 193,376	-3.7%
rest properties	186,114 → 180,948	-2.8%	200,787 → 183,051	🔴 -8.8%
object parameter	93,922 → 92,124	-1.9%	155,889 → 145,262	-6.8%
array parameter	121,364 → 117,365	-3.3%	122,439 → 107,130	🔴 -12.5%
mixed destructuring in map	33,540 → 32,304	-3.7%	37,159 → 35,003	-5.8%
forEach with array destructuring	63,671 → 61,929	-2.7%	47,833 → 41,504	🔴 -13.2%
map with array destructuring	63,324 → 61,817	-2.4%	45,799 → 40,806	🔴 -10.9%
filter with array destructuring	66,034 → 63,679	-3.6%	53,084 → 47,677	🔴 -10.2%
reduce with array destructuring	73,112 → 69,702	-4.7%	50,160 → 45,232	🔴 -9.8%
map with object destructuring	73,629 → 72,648	-1.3%	98,300 → 91,075	🔴 -7.4%
map with nested destructuring	61,497 → 60,525	-1.6%	93,795 → 86,095	🔴 -8.2%
map with rest in destructuring	42,444 → 40,468	-4.7%	27,040 → 23,356	🔴 -13.6%
map with defaults in destructuring	56,808 → 55,722	-1.9%	70,579 → 64,834	🔴 -8.1%

fibonacci.js — Interp: 8 unch. · avg -3.4% · Bytecode: 🔴 7, 1 unch. · avg -10.6%

Benchmark	Interpreted	Δ	Bytecode	Δ
recursive fib(15)	325 → 316	-2.7%	958 → 834	🔴 -12.9%
recursive fib(20)	30 → 29	-2.5%	86 → 76	🔴 -12.2%
recursive fib(15) typed	331 → 319	-3.6%	979 → 879	🔴 -10.2%
recursive fib(20) typed	30 → 29	-2.6%	90 → 79	🔴 -11.9%
iterative fib(20) via reduce	12,188 → 11,791	-3.3%	19,259 → 17,234	🔴 -10.5%
iterator fib(20)	9,689 → 9,220	-4.8%	19,523 → 18,215	-6.7%
iterator fib(20) via Iterator.from + take	15,409 → 14,961	-2.9%	22,124 → 20,154	🔴 -8.9%
iterator fib(20) last value via reduce	11,835 → 11,265	-4.8%	16,197 → 14,368	🔴 -11.3%

for-of.js — Interp: 7 unch. · avg -5.4% · Bytecode: 🔴 2, 5 unch. · avg -4.5%

Benchmark	Interpreted	Δ	Bytecode	Δ
for...of with 10-element array	46,511 → 43,547	-6.4%	176,714 → 170,113	-3.7%
for...of with 100-element array	5,347 → 4,996	-6.6%	18,532 → 18,478	-0.3%
for...of with string (10 chars)	34,197 → 33,761	-1.3%	91,542 → 87,509	-4.4%
for...of with Set (10 elements)	46,203 → 43,861	-5.1%	164,393 → 154,432	-6.1%
for...of with Map entries (10 entries)	29,939 → 28,188	-5.8%	29,473 → 27,201	🔴 -7.7%
for...of with destructuring	39,607 → 36,938	-6.7%	39,056 → 35,950	🔴 -8.0%
for-await-of with sync array	44,319 → 41,828	-5.6%	131,034 → 129,346	-1.3%

helpers/bench-module.js — Interp: 0 · Bytecode: 0

Benchmark	Interpreted	Δ	Bytecode	Δ

iterators.js — Interp: 🔴 5, 15 unch. · avg -5.7% · Bytecode: 🔴 19, 1 unch. · avg -11.4%

Benchmark	Interpreted	Δ	Bytecode	Δ
Iterator.from({next}).toArray() — 20 elements	15,559 → 14,664	-5.7%	21,958 → 19,925	🔴 -9.3%
Iterator.from({next}).toArray() — 50 elements	6,650 → 6,382	-4.0%	10,034 → 8,831	🔴 -12.0%
spread pre-wrapped iterator — 20 elements	11,383 → 10,968	-3.6%	21,092 → 19,131	🔴 -9.3%
Iterator.from({next}).forEach — 50 elements	4,615 → 4,376	-5.2%	6,384 → 5,527	🔴 -13.4%
Iterator.from({next}).reduce — 50 elements	4,709 → 4,455	-5.4%	6,363 → 5,412	🔴 -14.9%
wrap array iterator	165,626 → 159,701	-3.6%	205,029 → 175,885	🔴 -14.2%
wrap plain {next()} object	10,756 → 10,242	-4.8%	15,912 → 13,779	🔴 -13.4%
map + toArray (50 elements)	4,671 → 4,463	-4.5%	6,560 → 5,969	🔴 -9.0%
filter + toArray (50 elements)	4,560 → 4,328	-5.1%	6,826 → 5,806	🔴 -14.9%
take(10) + toArray (50 element source)	27,741 → 26,597	-4.1%	37,766 → 35,070	🔴 -7.1%
drop(40) + toArray (50 element source)	6,724 → 6,300	-6.3%	9,955 → 8,698	🔴 -12.6%
chained map + filter + take (100 element source)	8,302 → 7,784	-6.2%	11,954 → 10,210	🔴 -14.6%
some + every (50 elements)	2,699 → 2,466	🔴 -8.6%	3,939 → 3,502	🔴 -11.1%
find (50 elements)	5,856 → 5,381	🔴 -8.1%	7,762 → 7,304	-5.9%
array.values().map().filter().toArray()	8,252 → 7,595	🔴 -8.0%	11,029 → 9,762	🔴 -11.5%
array.values().take(5).toArray()	212,669 → 204,347	-3.9%	255,272 → 233,064	🔴 -8.7%
array.values().drop(45).toArray()	197,773 → 186,740	-5.6%	238,411 → 208,726	🔴 -12.5%
map.entries() chained helpers	10,341 → 9,537	🔴 -7.8%	6,603 → 5,847	🔴 -11.4%
set.values() chained helpers	17,329 → 16,294	-6.0%	22,650 → 19,918	🔴 -12.1%
string iterator map + toArray	13,522 → 12,548	🔴 -7.2%	15,736 → 14,244	🔴 -9.5%

json.js — Interp: 🔴 11, 9 unch. · avg -8.2% · Bytecode: 🔴 17, 3 unch. · avg -11.8%

Benchmark	Interpreted	Δ	Bytecode	Δ
parse simple object	174,016 → 164,645	-5.4%	192,978 → 176,788	🔴 -8.4%
parse nested object	107,123 → 100,074	-6.6%	114,076 → 107,605	-5.7%
parse array of objects	62,437 → 58,903	-5.7%	68,270 → 61,729	🔴 -9.6%
parse large flat object	67,978 → 65,381	-3.8%	76,847 → 70,250	🔴 -8.6%
parse mixed types	77,936 → 75,612	-3.0%	88,882 → 78,367	🔴 -11.8%
stringify simple object	196,570 → 174,130	🔴 -11.4%	231,748 → 187,976	🔴 -18.9%
stringify nested object	111,125 → 96,507	🔴 -13.2%	120,927 → 101,922	🔴 -15.7%
stringify array of objects	61,367 → 48,913	🔴 -20.3%	61,101 → 50,913	🔴 -16.7%
stringify mixed types	88,747 → 76,151	🔴 -14.2%	95,636 → 78,450	🔴 -18.0%
reviver doubles numbers	48,827 → 47,405	-2.9%	56,096 → 53,816	-4.1%
reviver filters properties	40,990 → 40,057	-2.3%	48,234 → 43,076	🔴 -10.7%
reviver on nested object	52,120 → 51,689	-0.8%	58,849 → 55,085	-6.4%
reviver on array	32,390 → 31,812	-1.8%	37,050 → 32,905	🔴 -11.2%
replacer function doubles numbers	47,500 → 43,905	🔴 -7.6%	57,149 → 49,438	🔴 -13.5%
replacer function excludes properties	60,535 → 55,509	🔴 -8.3%	67,360 → 59,339	🔴 -11.9%
array replacer (allowlist)	113,086 → 103,524	🔴 -8.5%	129,464 → 112,554	🔴 -13.1%
stringify with 2-space indent	97,136 → 81,412	🔴 -16.2%	105,268 → 92,001	🔴 -12.6%
stringify with tab indent	96,325 → 83,224	🔴 -13.6%	108,214 → 91,203	🔴 -15.7%
parse then stringify	55,610 → 50,621	🔴 -9.0%	62,659 → 55,511	🔴 -11.4%
stringify then parse	34,306 → 31,191	🔴 -9.1%	38,731 → 33,671	🔴 -13.1%

jsx.jsx — Interp: 21 unch. · avg -1.1% · Bytecode: 🔴 1, 20 unch. · avg -3.1%

Benchmark	Interpreted	Δ	Bytecode	Δ
simple element	210,383 → 209,744	-0.3%	323,526 → 331,290	+2.4%
self-closing element	219,434 → 218,747	-0.3%	369,840 → 352,561	-4.7%
element with string attribute	177,193 → 175,460	-1.0%	258,109 → 257,231	-0.3%
element with multiple attributes	157,621 → 153,362	-2.7%	208,001 → 201,632	-3.1%
element with expression attribute	167,960 → 163,617	-2.6%	258,894 → 255,411	-1.3%
text child	209,840 → 211,598	+0.8%	342,525 → 324,089	-5.4%
expression child	205,460 → 210,192	+2.3%	331,751 → 325,398	-1.9%
mixed text and expression	195,027 → 193,360	-0.9%	301,727 → 285,931	-5.2%
nested elements (3 levels)	80,402 → 80,064	-0.4%	124,657 → 120,429	-3.4%
sibling children	60,127 → 59,504	-1.0%	93,769 → 89,814	-4.2%
component element	150,384 → 149,302	-0.7%	227,712 → 224,348	-1.5%
component with children	92,565 → 92,167	-0.4%	142,284 → 131,891	🔴 -7.3%
dotted component	126,733 → 124,811	-1.5%	179,645 → 175,389	-2.4%
empty fragment	222,771 → 220,351	-1.1%	390,725 → 366,840	-6.1%
fragment with children	59,597 → 59,773	+0.3%	91,153 → 89,337	-2.0%
spread attributes	111,920 → 108,325	-3.2%	141,113 → 131,557	-6.8%
spread with overrides	97,307 → 94,482	-2.9%	120,500 → 118,701	-1.5%
shorthand props	162,603 → 156,962	-3.5%	240,062 → 233,654	-2.7%
nav bar structure	28,267 → 27,931	-1.2%	41,316 → 41,373	+0.1%
card component tree	32,374 → 32,075	-0.9%	46,404 → 43,623	-6.0%
10 list items via Array.from	14,871 → 14,508	-2.4%	19,942 → 19,428	-2.6%

modules.js — Interp: 9 unch. · avg -3.1% · Bytecode: 🔴 7, 2 unch. · avg -9.2%

Benchmark	Interpreted	Δ	Bytecode	Δ
call imported function	480,318 → 461,575	-3.9%	637,419 → 653,432	+2.5%
call two imported functions	269,701 → 259,307	-3.9%	362,256 → 353,148	-2.5%
read imported constant	1,638,335 → 1,579,496	-3.6%	4,108,713 → 3,647,257	🔴 -11.2%
read imported string	1,594,126 → 1,557,318	-2.3%	4,109,933 → 3,487,290	🔴 -15.1%
read JSON string property	1,636,034 → 1,569,907	-4.0%	4,076,285 → 3,654,247	🔴 -10.4%
read JSON number property	1,596,774 → 1,559,759	-2.3%	4,110,576 → 3,649,498	🔴 -11.2%
read JSON boolean property	1,632,399 → 1,573,223	-3.6%	4,111,840 → 3,647,539	🔴 -11.3%
read JSON array property	1,630,359 → 1,565,296	-4.0%	4,114,615 → 3,652,430	🔴 -11.2%
read multiple JSON properties	930,814 → 929,460	-0.1%	3,748,977 → 3,282,923	🔴 -12.4%

numbers.js — Interp: 🔴 1, 10 unch. · avg -3.2% · Bytecode: 🔴 7, 4 unch. · avg -9.9%

Benchmark	Interpreted	Δ	Bytecode	Δ
integer arithmetic	518,683 → 479,185	🔴 -7.6%	1,762,920 → 1,508,504	🔴 -14.4%
floating point arithmetic	592,826 → 578,936	-2.3%	1,276,611 → 806,465	🔴 -36.8%
number coercion	191,551 → 189,531	-1.1%	244,368 → 226,636	🔴 -7.3%
toFixed	100,895 → 98,345	-2.5%	122,407 → 111,278	🔴 -9.1%
toString	156,717 → 147,020	-6.2%	199,776 → 183,774	🔴 -8.0%
valueOf	230,266 → 216,834	-5.8%	289,190 → 279,439	-3.4%
toPrecision	145,114 → 138,521	-4.5%	171,868 → 165,771	-3.5%
Number.isNaN	321,359 → 327,182	+1.8%	365,282 → 338,889	🔴 -7.2%
Number.isFinite	325,524 → 317,189	-2.6%	343,024 → 325,133	-5.2%
Number.isInteger	326,493 → 327,483	+0.3%	383,790 → 357,773	-6.8%
Number.parseInt and parseFloat	257,048 → 245,649	-4.4%	290,199 → 268,312	🔴 -7.5%

objects.js — Interp: 🔴 1, 6 unch. · avg -4.6% · Bytecode: 7 unch. · avg -2.9%

Benchmark	Interpreted	Δ	Bytecode	Δ
create simple object	491,357 → 477,525	-2.8%	570,807 → 554,729	-2.8%
create nested object	235,544 → 221,790	-5.8%	263,544 → 253,177	-3.9%
create 50 objects via Array.from	9,274 → 8,955	-3.4%	10,168 → 9,819	-3.4%
property read	552,058 → 538,482	-2.5%	442,642 → 438,727	-0.9%
Object.keys	288,900 → 267,776	🔴 -7.3%	333,891 → 319,038	-4.4%
Object.entries	105,518 → 101,639	-3.7%	114,175 → 108,852	-4.7%
spread operator	180,968 → 168,474	-6.9%	210,751 → 210,908	+0.1%

promises.js — Interp: 12 unch. · avg -3.2% · Bytecode: 12 unch. · avg -4.2%

Benchmark	Interpreted	Δ	Bytecode	Δ
Promise.resolve(value)	542,388 → 537,836	-0.8%	587,855 → 572,245	-2.7%
new Promise(resolve => resolve(value))	191,677 → 189,790	-1.0%	236,737 → 232,203	-1.9%
Promise.reject(reason)	549,461 → 539,243	-1.9%	583,421 → 547,010	-6.2%
resolve + then (1 handler)	177,968 → 172,183	-3.3%	209,375 → 200,487	-4.2%
resolve + then chain (3 deep)	70,175 → 67,209	-4.2%	82,910 → 79,357	-4.3%
resolve + then chain (10 deep)	22,169 → 20,641	-6.9%	25,912 → 24,901	-3.9%
reject + catch + then	100,358 → 97,684	-2.7%	118,788 → 112,893	-5.0%
resolve + finally + then	84,697 → 81,897	-3.3%	95,847 → 92,083	-3.9%
Promise.all (5 resolved)	31,491 → 30,834	-2.1%	35,039 → 33,146	-5.4%
Promise.race (5 resolved)	33,498 → 31,844	-4.9%	36,767 → 35,312	-4.0%
Promise.allSettled (5 mixed)	26,537 → 25,681	-3.2%	29,205 → 28,128	-3.7%
Promise.any (5 mixed)	32,101 → 30,600	-4.7%	34,455 → 32,745	-5.0%

strings.js — Interp: 11 unch. · avg -4.1% · Bytecode: 🟢 1, 🔴 4, 6 unch. · avg -3.6%

Benchmark	Interpreted	Δ	Bytecode	Δ
string concatenation	408,262 → 385,484	-5.6%	298,311 → 320,633	🟢 +7.5%
template literal	616,385 → 632,591	+2.6%	650,554 → 656,614	+0.9%
string repeat	404,435 → 378,235	-6.5%	492,533 → 455,599	🔴 -7.5%
split and join	139,583 → 131,839	-5.5%	159,056 → 158,677	-0.2%
indexOf and includes	166,953 → 160,415	-3.9%	206,393 → 186,970	🔴 -9.4%
toUpperCase and toLowerCase	252,726 → 243,194	-3.8%	340,275 → 335,024	-1.5%
slice and substring	152,536 → 145,337	-4.7%	206,848 → 192,040	🔴 -7.2%
trim operations	185,839 → 176,194	-5.2%	246,979 → 245,521	-0.6%
replace and replaceAll	210,537 → 201,038	-4.5%	253,316 → 235,954	-6.9%
startsWith and endsWith	132,942 → 127,779	-3.9%	168,876 → 157,432	-6.8%
padStart and padEnd	194,154 → 185,814	-4.3%	244,894 → 225,458	🔴 -7.9%

typed-arrays.js — Interp: 🔴 1, 21 unch. · avg -3.7% · Bytecode: 🔴 14, 8 unch. · avg -9.0%

Benchmark	Interpreted	Δ	Bytecode	Δ
new Int32Array(0)	331,890 → 309,757	-6.7%	390,540 → 376,138	-3.7%
new Int32Array(100)	304,689 → 283,698	-6.9%	354,490 → 336,888	-5.0%
new Int32Array(1000)	183,682 → 173,667	-5.5%	225,700 → 201,379	🔴 -10.8%
new Float64Array(100)	276,911 → 261,621	-5.5%	339,187 → 315,154	🔴 -7.1%
Int32Array.from([...])	183,282 → 171,634	-6.4%	214,568 → 189,229	🔴 -11.8%
Int32Array.of(1, 2, 3, 4, 5)	311,950 → 299,456	-4.0%	352,698 → 364,202	+3.3%
sequential write 100 elements	3,529 → 3,390	-3.9%	17,526 → 15,785	🔴 -9.9%
sequential read 100 elements	3,570 → 3,429	-4.0%	11,561 → 11,172	-3.4%
Float64Array write 100 elements	3,271 → 3,117	-4.7%	12,852 → 8,786	🔴 -31.6%
fill(42)	46,523 → 46,802	+0.6%	59,683 → 47,025	🔴 -21.2%
slice()	197,321 → 197,366	+0.0%	241,384 → 219,909	🔴 -8.9%
map(x => x * 2)	8,022 → 7,656	-4.6%	9,651 → 8,819	🔴 -8.6%
filter(x => x > 50)	8,451 → 7,834	🔴 -7.3%	10,532 → 9,504	🔴 -9.8%
reduce (sum)	7,853 → 7,475	-4.8%	7,923 → 7,487	-5.5%
sort()	171,376 → 164,210	-4.2%	208,059 → 171,972	🔴 -17.3%
indexOf()	422,432 → 414,636	-1.8%	550,352 → 493,375	🔴 -10.4%
reverse()	321,898 → 318,922	-0.9%	393,791 → 351,579	🔴 -10.7%
create view over existing buffer	401,962 → 389,065	-3.2%	473,615 → 455,218	-3.9%
subarray()	420,311 → 419,899	-0.1%	532,944 → 517,966	-2.8%
set() from array	555,995 → 562,120	+1.1%	683,714 → 631,635	🔴 -7.6%
for-of loop	4,986 → 4,703	-5.7%	19,791 → 18,285	🔴 -7.6%
spread into array	17,116 → 16,625	-2.9%	101,733 → 97,870	-3.8%

_{Measured on ubuntu-latest x64. Changes within ±7% are considered insignificant.}

[github-actions]

Suite Timing

Suite	Metric	Interpreted	Bytecode
Tests	Total	3534	3534
Tests	Passed	3493 ✅	3534 ✅
Tests	Skipped	41	0
Tests	Execution	153.4ms	145.8ms
Tests	Engine	306.2ms	531.6ms
Benchmarks	Total	263	263
Benchmarks	Duration	7.16min	6.01min

_{Measured on ubuntu-latest x64.}