Repository navigation
Smaller API results that are silently wrong: util.inspect(Map/Set), Buffer#indexOf(string), url.pathToFileURL, 'newListener', hash.copy(), ArrayBuffer#transfer #59
Description
Test I ran
node util_misc.ts
slice run util_misc.tsutil_misc.ts
import * as util from "node:util";
import * as url from "node:url";
import * as crypto from "node:crypto";
import { EventEmitter } from "node:events";
const show = async (k: string, f: () => unknown) => { let v; try { v = await Promise.race([Promise.resolve().then(f), new Promise((r) => setTimeout(() => r("NEVER SETTLED (2000 ms)"), 2000))]); } catch (e: any) { v = "THROWS " + e.name + ": " + String(e.message).slice(0, 100); } console.log(k.padEnd(52) + JSON.stringify(v)); };
(async () => {
await show("util.inspect(new Map([[1,{a:1}]]))", () => util.inspect(new Map([[1, { a: 1 }]])));
await show("util.inspect(new Set([1,'a']))", () => util.inspect(new Set([1, "a"])));
await show("util.format('%o', new Map([[1,2]]))", () => util.format("%s", new Map([[1, 2]])));
await show("util.inspect(obj, {depth: 0})", () => util.inspect({ a: { b: 1 } }, { depth: 0 }));
await show("util.inspect deep default depth (2)", () => util.inspect({ a: { b: { c: { d: 1 } } } }));
await show("util.inspect(new Error('x')) has stack", () => /Error: x\n\s+at /.test(util.inspect(new Error("x"))));
await show("url.pathToFileURL('/a/b c.txt').href", () => url.pathToFileURL("/a/b c.txt").href);
await show("EventEmitter 'newListener' event", () => { const e = new EventEmitter(); const o: string[] = []; e.on("newListener", (n) => o.push(String(n))); e.on("z", () => {}); return o; });
await show("Buffer#indexOf('ca') / includes('b')", () => [Buffer.from("abcabc").indexOf("ca"), Buffer.from("abc").includes("b"), Buffer.from("abc").indexOf(Buffer.from("c")), Buffer.from("abc").indexOf(0x62)]);
await show("Buffer.from('ab','utf16le').length", () => Buffer.from("ab", "utf16le").length);
await show("crypto.createHash('sha256').copy()", () => { const h = crypto.createHash("sha256").update("a"); const c = h.copy(); return [h.digest("hex").slice(0, 8), c.update("b").digest("hex").slice(0, 8)]; });
await show("ArrayBuffer.prototype.transfer", () => { const b = new ArrayBuffer(8); const t = b.transfer(); return [t.byteLength, b.detached]; });
await show("resizable ArrayBuffer .resize()", () => { const b = new ArrayBuffer(8, { maxByteLength: 16 }); b.resize(12); return b.byteLength; });
})();Result
Node v24.22.2:
util.inspect(new Map([[1,{a:1}]])) "Map(1) { 1 => { a: 1 } }"
util.inspect(new Set([1,'a'])) "Set(2) { 1, 'a' }"
util.format('%o', new Map([[1,2]])) "Map(1) { 1 => 2 }"
util.inspect(obj, {depth: 0}) "{ a: [Object] }"
util.inspect deep default depth (2) "{ a: { b: { c: [Object] } } }"
util.inspect(new Error('x')) has stack true
url.pathToFileURL('/a/b c.txt').href "file:///a/b%20c.txt"
EventEmitter 'newListener' event ["z"]
Buffer#indexOf('ca') / includes('b') [2,true,2,1]
Buffer.from('ab','utf16le').length 4
crypto.createHash('sha256').copy() ["ca978112","fb8e20fc"]
ArrayBuffer.prototype.transfer [8,true]
resizable ArrayBuffer .resize() 12
Slice v0.10.7:
util.inspect(new Map([[1,{a:1}]])) "{}"
util.inspect(new Set([1,'a'])) "{}"
util.format('%o', new Map([[1,2]])) "[object Map]"
util.inspect(obj, {depth: 0}) "THROWS TypeError: not a callable function"
util.inspect deep default depth (2) "{ a: { b: { c: { d: 1 } } } }"
util.inspect(new Error('x')) has stack false
url.pathToFileURL('/a/b c.txt').href "file:///a/b c.txt"
EventEmitter 'newListener' event []
Buffer#indexOf('ca') / includes('b') [-1,false,-1,1]
Buffer.from('ab','utf16le').length 2
crypto.createHash('sha256').copy() "THROWS TypeError: not a callable function"
ArrayBuffer.prototype.transfer "THROWS TypeError: not a callable function"
resizable ArrayBuffer .resize() 12
What is wrong
| API | Slice | Node | Listed in COMPATIBILITY.md? |
|---|---|---|---|
util.inspect(new Map(...)), util.inspect(new Set(...)) |
{} (contents dropped) |
Map(1) { 1 => { a: 1 } } |
util.inspect yes |
util.inspect(obj, { depth: 0 }) |
throws TypeError: not a callable function |
{ a: [Object] } |
yes |
util.inspect default depth |
nested objects printed past depth 2 | stops at depth 2 ([Object]) |
yes |
util.inspect(new Error("x")) |
no stack | message + stack | yes |
Buffer#indexOf("ca"), #includes("b"), #indexOf(Buffer) |
-1, false, -1 |
2, true, 2 |
no (falls back to Uint8Array#indexOf) |
Buffer.from("ab", "utf16le").length |
2 | 4 | no |
url.pathToFileURL("/a/b c.txt").href |
file:///a/b c.txt |
file:///a/b%20c.txt |
yes |
EventEmitter 'newListener' event |
not emitted | emitted | "Full EventEmitter class" |
crypto.createHash(...).copy() |
throws | works | no |
ArrayBuffer.prototype.transfer() |
throws | works | yes, in §6 ("ArrayBuffer transfer/resize") |
Grouped into one issue because each is small. The Buffer#indexOf / #includes rows return a wrong answer instead of throwing, which is why they are here even though the matrix does not claim them.
Environment
- Slice
v0.10.7, commitea7c70c, built withcargo +1.96.0 build --release --locked --bin slice - Reference: Node.js
v24.22.2(same script, same machine) - Ubuntu 26.04, Linux 7.0, x86_64
- The same output is produced by the
v0.10.5tag, so this is not a regression in 0.10.6/0.10.7.
Activity
siktec-lab commentedon Nov 11, 2026
Addressed in #67 (�0.10.11): implemented util.inspect depth/Map/Set/Error formatting (util.format('%s', map)), Buffer#indexOf/lastIndexOf/includes, url.pathToFileURL percent-encoding (%, #, ?, spaces), EventEmitter 'newListener'/'removeListener' events, crypto.createHash#copy(), and enabled ES2024 ArrayBuffer.prototype.transfer / ransferToFixedLength / detached.