vant-weapp/dist/tab/index.js

import { VantComponent } from '../common/component';
VantComponent({
    relation: {
        name: 'tabs',
        type: 'ancestor'
    },
    props: {
        title: String,
        disabled: Boolean
    },
    data: {
        inited: false,
        active: false
    },
    watch: {
        disabled() {
            const parent = this.getRelationNodes('../tabs/index')[0];
            if (parent) {
                parent.updateTabs();
            }
        },
        title() {
            const parent = this.getRelationNodes('../tabs/index')[0];
            if (parent) {
                parent.setLine();
                parent.updateTabs();
            }
        }
    }
});