answer-mini/wechat-app/static/vant/nav-bar/index.wxml

<wxs src="../wxs/utils.wxs" module="utils" />

<view wx:if="{{ fixed && placeholder }}" style="height: {{ height }}px;" />

<view
  class="{{ utils.bem('nav-bar', { fixed }) }} custom-class {{ border ? 'van-hairline--bottom' : '' }}"
  style="{{ baseStyle }}; {{ customStyle }}"
>
  <view class="van-nav-bar__content">
    <view class="van-nav-bar__left" bind:tap="onClickLeft">
      <block wx:if="{{ leftArrow || leftText }}">
        <van-icon
          wx:if="{{ leftArrow }}"
          size="16px"
          name="arrow-left"
          custom-class="van-nav-bar__arrow"
        />
        <view
          wx:if="{{ leftText }}"
          class="van-nav-bar__text"
          hover-class="van-nav-bar__text--hover"
          hover-stay-time="70"
        >{{ leftText }}</view>
      </block>
      <slot wx:else name="left" />
    </view>
    <view class="van-nav-bar__title title-class van-ellipsis">
      <block wx:if="{{ title }}">{{ title }}</block>
      <slot wx:else name="title" />
    </view>
    <view class="van-nav-bar__right" bind:tap="onClickRight">
      <view
        wx:if="{{ rightText }}"
        class="van-nav-bar__text"
        hover-class="van-nav-bar__text--hover"
        hover-stay-time="70"
      >{{ rightText }}</view>
      <slot wx:else name="right" />
    </view>
  </view>
</view>