Add mergeProps argument

[simenbrekken]

Closes #19

[einarlove]

Shouldn't actionProps be the last argument seen it will be the least used?

[simenbrekken]

Won't all of them almost always be used? Otherwise your function would be discarding arguments.

[einarlove]

const customMerge = (ownProps, ...rest) => ({
  ...rest,
  prop: ownProps.prop || rest.prop,
})

[simenbrekken]

I reordered the arguments in the latest commit, let me know what you think.

[einarlove]

Can you give an example where it is necessary to have subscriptionProps and actionProps as seperate arguments?

[simenbrekken]

We could merge them before passing them into mergeProps as they will never collide, but an efficient cascading implementation would still be:

const assignCustomizer = (objectValue, sourceValue) => (
  _.isNil(objectValue) ? sourceValue : objectValue
)

const customMergeProps = (actionProps, subscriptionProps, ownProps) => {
  const cascadedProps = _.assignWith({}, ownProps, subscriptionProps, assignCustomizer)

  return {
    ...actionProps,
    ...cascadedProps
  }
}

[einarlove]

Why can't we do

const props = mergeProps(this.props, { ...actionProps, ...subscriptionProps })

instead? Why should the developer get three arguments to mergeProps?

[simenbrekken]

If you'd want to add defaults to subscriptionProps as in the example above you would have to filter out actionProps by checking if they are functions or values.

[einarlove]

Could you give an example?

[simenbrekken]

#20 (comment)

[simenbrekken]

Once again, Circle refuses to run tests so I'm merging this manually.