child_process documentation for stdio

[skovhus]

The child_process documentation for execFileSync, execSync and spawnSync notes that options.stdio is an array.

But it seems it can also be a string, similar to the stdio options given to child_process.spawn.

Actually execFileSync, execSync and spawnSync all ends up here, where the options are accepted as string or array. See https://github.com/nodejs/node/blob/master/lib/internal/child_process.js#L758

[sam-github]

To be clear: that it can be a String is documented: https://nodejs.org/api/child_process.html#child_process_options_stdio, but not described in the type annotations.

[skovhus]

@sam-github but a bit confusing when child_process.fork is documented in the same context, but it doesn't support it being a string.

[sam-github]

That fork doesn't support String is a documented (https://nodejs.org/api/child_process.html#child_process_child_process_fork_modulepath_args_options) misfeature, if you PR a fix with test code, I'd happily LGTM it!

Randomly different APIs that could be the same are maddening :-(