vant/packages/step/index.vue

<template>
  <div class="van-step van-hairline" :class="[`van-step--${$parent.direction}`, { [`van-step--${status}`]: status }]">
    <div class="van-step__circle-container">
      <i class="van-step__circle" v-if="status !== 'process'" />
      <i class="van-icon van-icon-checked" :style="{ color: $parent.activeColor }" v-else />
    </div>
    <div class="van-step__title" :style="titleStyle">
      <slot></slot>
    </div>
    <div class="van-step__line" />
  </div>
</template>

<script>
export default {
  name: 'van-step',

  beforeCreate() {
    this.$parent.steps.push(this);
  },

  computed: {
    status() {
      const index = this.$parent.steps.indexOf(this);
      const active = this.$parent.active;

      if (index < active) {
        return 'finish';
      } else if (index === active) {
        return 'process';
      }
    },

    titleStyle() {
      return this.status === 'process' ? {
        color: this.$parent.activeColor
      } : {};
    }
  }
};
</script>