Float32Array.buffer instanceof ArrayBuffer returns false in latest release

[gkjohnson]

🐛 Bug Report

In the latest version of Jest (26.6.3) new Float32Array( 1 ).buffer instanceof ArrayBuffer returns false causing tests to fail.

To Reproduce

The following test fails in v26.6.3 but passes in v25.5.4 with no extra configuration:

describe('Float32Array.buffer', () => {
    it('should be an instance of ArrayBuffer', () => {
        expect(new Float32Array().buffer instanceof ArrayBuffer).toBeTruthy();
    });
});

Expected behavior

That new Float32Array().buffer instanceof ArrayBuffer return true like it does in the browser and node.

envinfo

  System:
    OS: macOS High Sierra 10.13.6
  Binaries:
    Node: 13.8.0
    Yarn: 1.10.1
    npm: 6.13.7
  npmPackages:
    jest: ^26.6.3 => 26.6.3 

[ExE-Boss]

That’s because Jest uses a new VM context, and overrides the VM context’s ArrayBuffer with the top‑level global object’s ArrayBuffer, but doesn’t do this for typed arrays, which construct their ArrayBuffers using the overwritten ArrayBuffer constructor:

new Uint8Array().buffer.constructor !== ArrayBuffer;

Regressed by: #9606

[gkjohnson]

Awesome -- thanks for the fix!

[github-actions]

This issue has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.
Please note this issue tracker is not a help forum. We recommend using StackOverflow or our discord channel for questions.