Adding slides dynamically with v-for

[moteey]

I have a case where I need to display slides from an array with v-for.

If I have the array in component's data function, everything works fine (seems like slides are initialized when the slideshow is mounted).

However, if my array is empty when the slideshow is mounted, and later changed (via Vuex), then I get the following error:

[Vue warn]: Error in mounted hook: "TypeError: Cannot set property 'step' of undefined"

Is it possible to render slides with v-for if the data is not yet available when component is mounted?

[yaodingyd]

Two step:

1. your array has to have at least 1 slide for now. It can be empty slide like <slide/>, but there must be at least 1 slide for slideshow to initialize properly.
2. After your state changed You can call 'findSlides()' to reinitialize

[moteey]

Thanks, that was very helpful!

[moteey]

One more question though. What is the best way to remove the first (empty) slide when the state changes?
Looking at the findSlides() method it seems to push new slides onto the existing array, without resetting it first...

[yaodingyd]

Can you do it in your state setting? something like initial state is one dummy slide, then vuex will mutate state to your real slides?

[moteey]

I'm doing something similar, yes.

Problem is that this.slides ends up with one item too many after calling this.findSlides() for the second time. Probably because that method adds onto this.slides, so the "dummy" slide is never removed from there.

That results in one extra step in the beginning, so I have to press "Next" to go to the first slide.

Pasting a simplified example below (change of the state in afterMounted method, to hide Vuex complexity):

Template:

<slide v-for="mySlide in mySlides">
  {{mySlide}}
</slide>

Script:

data () {
  return {
    mySlides: ['dummy']
  }
},
methods: {
  afterMounted () {
    this.mySlides = ['real1', 'real2', 'real3']

    setTimeout(() => {
      this.findSlides()

      console.log(this.slides.length) // returns 4 instead of 3
    }, 10)
  }
}

[yaodingyd]

That's a valid point. Sometime ago I was thinking that should be a method initSlides that init from a clean state. Right now I thinking that findSlides should reset slide to empty array.

[yaodingyd]

Actually, you can manually set this.slides be to empty before this.findSlides

[moteey]

Yeah, was still running into issues when I did that - having an empty slide at the beginning.

Turns out that this.currentSlide was still holding a reference to the old slide, so I did this: this.currentSlide = this.slides[0] (after calling this.findSlides()).

This seems to solve it for now 👍

initSlides could be useful indeed, since it would probably to all this manual work behind the scenes.

[yaodingyd]

If you want to do it, a PR is welcome

[killua99]

@moteey could I see a code snipe of that implementation? Thanks

[yaodingyd]

findSlides would do initialization correctly in v0.4.2