[graphiql] Setting defaultHeaders causes TypeError: doc.iter is not a function

[netcoding87]

Is there an existing issue for this?

• I have searched the existing issues

Current Behavior

Creating an example based on Unpkg (CDN), I want to add defaultHeaders additionally doing it so:

...
root.render(
      React.createElement(GraphiQL, {
        fetcher,
        defaultEditorToolsVisibility: true,
        defaultHeaders: { 'foo': 'bar' },
        plugins: [explorerPlugin],
      }),
    );

When loading the page I get this on the console:

Expected Behavior

Page loads with default Headers set.

Steps To Reproduce

Open https://codesandbox.io/p/sandbox/7my5dd
See console output

Environment

• GraphiQL Version:
• OS:
• Browser:
• Bundler:
• react Version:
• graphql Version:

Anything else?

No response

[acao]

@netcoding87 I will check into this when I get a chance, but I think this is supposed to be a string instead of an object! Either way we should supply some runtime duck typing to make this more obvious for non TS users