I'm writing an extension to the extension "Binary File Viewer" for VS Code. My code is

/**
 * Select the 'aid' extension.
 */
registerFileType((fileExt, filePath, fileData) => {
    return fileExt == 'wav';
});

registerParser(() => {
    const buffer = new ArrayBuffer(4);

    let temp = new DataView(buffer);
    temp.setInt32(0, 123)
    let I = String(temp.getFloat32());
    addRow('I', I, '');
});

When I run it (actually, when it's involved by the Binary File Viewer), I have an error "Type error: ArrayBuffer is not a constructor". What I've done wrong?