React/Redux, how to get user input

Question

i am following the usage with React Redux tutorial. Something I really don't get is how to retrieve user input.

They build a FilterLink container, whose mapDispatchToProps is

const mapDispatchToProps = (dispatch, ownProps) => {
  return {
    onClick: () => {
      dispatch(setVisibilityFilter(ownProps.filter))
    }
  }
}

So it injects its ownProps.filter to the connected presentational component. If we go and see how this container is construced

const Footer = () => (
  <p>
    Show:{" "}
    <FilterLink filter="SHOW_ALL">All</FilterLink>{", "}
    <FilterLink filter="SHOW_ACTIVE">Active</FilterLink>{", "}
    <FilterLink filter="SHOW_COMPLETED">Completed</FilterLink>
  </p>
)

Ok, there is the "filter" property. That's clear.

Now I want to build a text filter on the same example. So first here is my presentational component

const TodoSearch = ({onSubmit}) => (
    <form
        onSubmit={e => {
            e.preventDefault()
            onSubmit()
        }}
    >
        <input placeholder="Text search" />
        <input type="submit" value="Go" />
    </form>
)

But when I come to write the container I don't know how to get user input

const mapDispatchToProps = (dispatch) => {
    return {
        onSubmit: () => {
            dispatch(setTextSearch(????))
        }
    }
}

It's something I would do with jQuery $(#text).val() but... is it the best way?

Later on on the same tutorial they build a little form to add a todo to the list. Ok, let's go and see how they catch input then.

let AddTodo = ({ dispatch }) => {
    let input

    return (
        <div>
            <form onSubmit={e => {
                e.preventDefault()
                if (!input.value.trim()) {
                    return
                }
                dispatch(addTodo(input.value))
                input.value = ''
             }}>
                 <input ref={node => {
                     input = node
                 }} />
                 <button type="submit">
                    Add Todo
                 </button>
            </form>
        </div>
    )
}

Wait, where's the magic here? Did they inject value into "input" variabile with that ref trick? Is that correct? So if there were 20 input fields, have I to use 20 variables with 20 different refs?

Any help is appreciate, thank you

Answer 1

Change your submit function to the following.

const mapDispatchToProps = (dispatch) => {
    return {
        onSubmit: (evt) => {
            dispatch(setTextSearch(evt.target.querySelector('input').value)
        }
    }
}

Also,

const TodoSearch = ({onSubmit}) => (
    <form
        onSubmit={e => {
            e.preventDefault()
            onSubmit(e)
        }}
    >
        <input placeholder="Text search" />
        <input type="submit" value="Go" />
    </form>
)