get colors from wp rest api

getColorbyRGBaster.js

const getColor = (posts) => {
    for (const key in posts) {
        if (posts[key]._embedded['wp:featuredmedia']) { // キャッチ画像が設定されている場合
            var imgUrl = posts[key]._embedded['wp:featuredmedia'][0].media_details.sizes.thumbnail.source_url;
            RGBaster.colors(imgUrl, { // eslint-disable-line
                paletteSize: 3,
                success: function (colors) {
                    Vue.set(vm.posts[key], 'color', colors.secondary);// eslint-disable-line
                    Vue.set(vm.posts[key], 'isLoaded', true);// eslint-disable-line
                }
            });
        } else {
            Vue.set(vm.posts[key], 'color', '#eee');// eslint-disable-line
            Vue.set(vm.posts[key], 'isLoaded', true);// eslint-disable-line
        }
    }
};

vue.html

<article class="m-card" v-bind:id="'post-' + post.id" v-for="post in posts">
   <div class="m-media">
        <a v-bind:href="post.link" class="a-color__container" v-bind:class="{'is-loaded' : post.isLoaded }">
        	<span class="a-color" v-bind:style="{ background: post.color }"></span>
            <span v-if="post._embedded['wp:featuredmedia']"><img :src="post._embedded['wp:featuredmedia'][0].source_url" alt=""></span>
        </a>
    </div>
</article>