`TextEncoder.encodeInto` from `node:util` does not throw TypeError

[davidebombelli]

What version of Bun is running?

1.3.14+0d9b296af

What platform is your computer?

Linux 6.8.0-136-generic x86_64 x86_64

What steps can reproduce the bug?

Run the following snippet:

const assert = require('node:assert');
const util = require('util');

const selectedTextEncoder = util.TextEncoder;

(function () {

    try {
        const enc = new selectedTextEncoder();
        const dest = new Int8Array(10);

        assert.throws(() => enc.encodeInto('abc', dest), TypeError, " The \"dest\" argument must be an instance of Uint8Array. Received an instance of Int8Array");
    } 
    catch (e) {
        console.log(e);      
    }

})();

What is the expected behavior?

in Node.js, no exception or error is output. This is because the assert at line 12 is successful (encodeInto throws a TypeError).

What do you see instead?

in Bun, the following is output:

AssertionError [ERR_ASSERTION]: Missing expected exception (TypeError):  The "dest" argument must be an instance of Uint8Array. Received an instance of Int8Array
    at <anonymous> (/home/username/test.js:12:16)
    at <anonymous> (/home/username/test.js:15:22) {
  generatedMessage: false,
  actual: undefined,
  expected: [Function: TypeError],
  operator: 'throws',
  code: 'ERR_ASSERTION'
}

which means that encodeInto is not throwing, even though it should.

Additional information

No response

[robobun]

Reproduced on 1.3.14: encodeInto accepts any ArrayBufferView instead of requiring Uint8Array, so the expected TypeError never fires. A fix is already open in #34726 (downcasts to Uint8Array and throws the same ERR_INVALID_ARG_TYPE TypeError as Node). This issue will be resolved when that PR lands.