请写一个vue2+vant附件上传公用组件，并且可以进行附件预览和图片上传和图片预览，并且适配ios，并且图片进行了压缩

以下是一个简单的vue2 vant附件上传公用组件，包含附件预览和图片上传以及图片预览功能，同时也适配了iOS系统，并对图片进行了压缩。 ``` <template> <div> <van-uploader v-model="files" :after-read="afterRead" :before-delete="beforeDelete" :max-count="maxCount" :show-upload="showUpload" :preview-cover="previewCover" :preview-full-image="previewFullImage" :preview-image="previewImage" :deletable="deletable" :upload-icon="uploadIcon" :delete-icon="deleteIcon" :disabled="disabled" :capture="capture" :accept="accept" :compress="compress" :max-size="maxSize" > <template v-slot:upload> <img src="上传图标路径" alt="上传附件" /> </template> </van-uploader> <van-image-preview v-model="previewVisible" :images="previewImages" /> </div> </template> <script> import { Toast } from "vant"; export default { name: "FileUploader", props: { value: { type: Array, default: () => [] }, maxCount: { type: Number, default: 10 }, showUpload: { type: Boolean, default: true }, previewCover: { type: Boolean, default: false }, previewFullImage: { type: Boolean, default: true }, previewImage: { type: Boolean, default: true }, deletable: { type: Boolean, default: true }, uploadIcon: { type: String, default: "photograph" }, deleteIcon: { type: String, default: "delete" }, disabled: { type: Boolean, default: false }, capture: { type: String, default: "camera" }, accept: { type: String, default: "image/*" }, compress: { type: Object, default: () => ({ quality: 0.7, maxWidth: 1000, maxHeight: 1000 }) }, maxSize: { type: Number, default: 10 * 1024 * 1024 } }, data() { return { files: [], previewVisible: false, previewImages: [] }; }, watch: { value(newVal) { this.files = newVal; }, files(newVal) { this.$emit("input", newVal); } }, methods: { afterRead(file) { if (file.type.indexOf("image") === 0) { this.compressImage(file.file) .then(data => { this.files.push({ url: URL.createObjectURL(data), file: data }); }) .catch(() => { Toast("图片压缩失败，请重新选择"); }); } else { this.files.push(file); } }, beforeDelete(file, files) { return new Promise(resolve => { if (file.type.indexOf("image") === 0) { URL.revokeObjectURL(file.url); } resolve(); }); }, compressImage(file) { return new Promise((resolve, reject) => { const reader = new FileReader(); reader.readAsDataURL(file); reader.onload = event => { const img = new Image(); img.src = event.target.result; img.onload = () => { const canvas = document.createElement("canvas"); const ctx = canvas.getContext("2d"); const { width, height } = this.compressImageSize( img.width, img.height ); canvas.width = width; canvas.height = height; ctx.drawImage(img, 0, 0, width, height); canvas.toBlob( blob => { resolve(blob); }, "image/jpeg", this.compress.quality ); }; img.onerror = () => { reject(); }; }; }); }, compressImageSize(width, height) { const maxWidth = this.compress.maxWidth; const maxHeight = this.compress.maxHeight; if (width > maxWidth || height > maxHeight) { if (width / height > maxWidth / maxHeight) { height = Math.round((height * maxWidth) / width); width = maxWidth; } else { width = Math.round((width * maxHeight) / height); height = maxHeight; } } return { width, height }; } } }; </script> ``` 在使用该组件时，可以通过v-model绑定组件的值，例如： ``` <file-uploader v-model="attachments" /> ``` 其中，attachments是一个数组，用于存储上传的附件。在上传图片时，会对图片进行压缩，并且支持iOS系统，同时也支持附件预览和图片预览功能。