Option to prevent two-way binding?

[Rich-Harris]

A lot of people have internalized the FUD around two-way binding to the extent that they're turned off Svelte altogether, notwithstanding the fact that it's optional and explicitly opt-in. I wonder if the compiler should have an option that prevents bindings from being used, so the 'we lost our second round of financing because a junior dev added a bind: directive' scenario doesn't arise

[proyb6]

I would welcome this, have never like two-way binding.

[chrisdavies]

I like two-way binding when I want it. Here's a scenario that I often run into:

I have an edit form. I want it to edit a copy, and only commit the edits when the user saves. I want 2-way binding on that copy, but it shouldn't update the original (in some global array somewhere).

The way I like to do this is to pass the original into my form component, and in my form component's initialize method, I create a copy of the data.

It would be nice to be able to access the passed-in values in a components data method:

import UserCard from './user_card.html';
export default {
  data(params) {
    return {
      tmp: copyObject(params.user)
    }
  },
  components: {UserCard}
}

This would be really handy.

[chrisdavies]

As a followup to my last comment, this seems to work pretty well for getting a tmp property that is a copy of a the user object:

    computed: {
      tmp: user => {
        return Object.assign({}, user);
      }
    },

[TehShrike]

When I use Redux with Ractive, I disable two-way binding to avoid accidentally mutating state. If/when I hook up Redux to Svelte, I imagine I'd want the same option.

[PaulBGD]

Is this literally requesting an option to disable the bind: directive?

[Rich-Harris]

yep