message: Uploader: optimize template
diff: <template>
  <div class="van-uploader">
  <slot></slot>
  - <template v-if="disabled">
  - <input type="file" @change="onValueChange" disabled="disabled" class="van-uploader__input" />
  - </template>
  - <template v-else>
  - <input type="file" @change="onValueChange" class="van-uploader__input" ref="input" />
  - </template>
  + <input type="file" @change="onValueChange" :disabled="disable" class="van-uploader__input" ref="input" />
  </div>
  </template>
  <script>
  export default {
  name: 'van-uploader',
  +
  props: {
  - disabled: {
  + disable: {
  type: Boolean,
  default: false
  },
  resultType: {
  type: String,
  default: 'dataUrl',
  - validator(value) {
  - return value === 'dataUrl' || value === 'text';
  - }
  + validator: value => value === 'dataUrl' || value === 'text'
  }
  },
  +
  methods: {
  onValueChange(event) {
  - if (this.disabled) {
  + if (this.disable) {
  return;
  }
  - var files = event.target.files;
  - var file = files[0];
  - if (!file) return;
  - if (this.beforeRead && !this.beforeRead(file)) return;
  - var reader = new FileReader();
  +
  + const file = event.target.files[0];
  + if (!file || (this.beforeRead && !this.beforeRead(file))) {
  + return;
  + }
  +
  + const reader = new FileReader();
  reader.onload = (e) => {
  - this.afterRead && this.afterRead(
  - {
  - file: file,
  + this.afterRead && this.afterRead({
  + file,
  content: e.target.result
  });
  this.$refs.input && (this.$refs.input.value = '');
  };
  +
  if (this.resultType === 'dataUrl') {
  reader.readAsDataURL(file);
  } else if (this.resultType === 'text') {
  