Accept undefined and null in plugins array

[silverwind]

Is your feature request related to a problem? Please describe.

To conditionally add plugins, && syntax is useful and this works in vite as well:

export default {plugins: [condition && SomePlugin()]}

It errors because the schema is too strict:

[webpack-cli] Invalid configuration object. Webpack has been initialized using a configuration object that does not match the API schema.
 - configuration.plugins[4] should be one of these:
   object { apply, … } | function
   -> Plugin of type object or instanceof Function.
   Details:
    * configuration.plugins[4] should be an object:
      object { apply, … }
      -> Plugin instance.
    * configuration.plugins[4] should be an instance of function.
      -> Function acting as plugin.

Describe the solution you'd like

Accept undefined and null values in plugins array, and just ignore them.

Describe alternatives you've considered

This works, but is clumsy:

export default {plugins: [condition && SomePlugin()].filter(Boolean)}

[alexander-akait]

I think we need improve this on the webpack side, because you can pass options without webpack-cli, feel free to send a PR

[silverwind]

I tried but then I gave up.

[hardfist]

webpack side seems more ideal，otherwise all webpack cli have to reimplement the same logic here