vuejs 2 component base64 image not updating

问题

what i want to achieve:
load an image from jwt token protected source
the server return the image as base64 string and i'll load this string as background url on the image

parent component:

<template lang="html">
     <myImage v-for="photo in form.photos" :photo="photo" @delphoto="deleteImage"></myImage>
</template>

export default {
        components: {
            myImage,
        },
        data(){
            return {
                form: {
                    photos: [
                {
            id: 1,
            thumbnail: "logo1.png"
            },
                {
            id: 2,
            thumbnail: "logo2.png"
            },
                {
            id: 3,
            thumbnail: "logo3.png"
            },
                {
            id: 4,
            thumbnail: "logo4.png"
            },
            ]

                },

            }
        },
        methods: {
            deleteImage(myphoto)
            {
                this.form.photos.splice(this.form.photos.indexOf(myphoto), 1);
            }
        }
    }

myImage component

<template>
        <div v-if="loaded" class="img">
            <img class="albumimg" :style="{ background: img}" :title="title">
            <p @click="delimage">delete</p>
        </div>
        <div v-else class="img">
            <img class="loading" style="background: url('/images/spinner.gif')">
        </div>
</template>
<script>
    export default {
        data(){
            return {
                img: null,
                loaded: false
            }
        },
        props: {
            photo: {
                required: true
            },
            title: {
                default: ''
            },
        },
        created() {
            this.imgurl()
        },
        methods: {
            delimage() {
              this.$emit('delphoto', this.photo)
            },
            imgurl() {
                this.$http.get("/api/images/" + this.photo.id).then(response => {
                    this.img = "url('" + response.data + "')"
                    this.loaded = true
                }, response => {
                });
            },
        }
    }
</script>

now if i delete a photo (splice) from the form.photos array always the last image get removed. when i remove the green image

the blue image disappears

when i check the form.photos array, the correct image was removed, only the img data attribute from myImage component is still the old value from the previous array position 1.

i was able to bypass this issue by adding a watch on the photo prop and refetch the base64 string which cause a new get request for every image

watch: {
   photo: function (val) {
      this.imgurl()
   }
},

is there any way to remove an array item (child component) and display the correct result without fetching all images again within the child component?

thanks

回答1:

Try this.

<myImage v-for="photo in form.photos" :key="photo.id" :photo="photo" @delphoto="deleteImage"></myImage>

From the current documentation.

In 2.2.0+, when using v-for with a component, a key is now required.

来源：https://stackoverflow.com/questions/43214344/vuejs-2-component-base64-image-not-updating