feat: add Empty component (#6010)

src/empty/index.js

@@ -0,0 +1,58 @@
+import { createNamespace } from '../utils';
+
+const [createComponent, bem] = createNamespace('empty');
+
+const PRESETS = ['error', 'search', 'default', 'network'];
+
+export default createComponent({
+  props: {
+    description: String,
+    image: {
+      type: String,
+      default: 'default',
+    },
+  },
+
+  computed: {
+    url() {
+      if (PRESETS.indexOf(this.image) !== -1) {
+        return `https://img.yzcdn.cn/vant/empty-image-${this.image}.png`;
+      }
+
+      return this.image;
+    },
+  },
+
+  methods: {
+    genImage() {
+      const image = this.slots('image') || <img src={this.url} />;
+      return <div class={bem('image')}>{image}</div>;
+    },
+
+    genDescription() {
+      const description = this.slots('description') || this.description;
+
+      if (description) {
+        return <p class={bem('description')}>{description}</p>;
+      }
+    },
+
+    genBottom() {
+      const slot = this.slots();
+
+      if (slot) {
+        return <div class={bem('bottom')}>{slot}</div>;
+      }
+    },
+  },
+
+  render() {
+    return (
+      <div class={bem()}>
+        {this.genImage()}
+        {this.genDescription()}
+        {this.genBottom()}
+      </div>
+    );
+  },
+});