BookStack/resources/js/components/tag-manager.js

import {Component} from './component';

export class TagManager extends Component {

    setup() {
        this.addRemoveComponentEl = this.$refs.addRemove;
        this.container = this.$el;
        this.rowSelector = this.$opts.rowSelector;

        this.setupListeners();
    }

    setupListeners() {
        this.container.addEventListener('input', event => {
            /** @var {AddRemoveRows} * */
            const addRemoveComponent = window.$components.firstOnElement(this.addRemoveComponentEl, 'add-remove-rows');
            if (!this.hasEmptyRows() && event.target.value) {
                addRemoveComponent.add();
            }
        });
    }

    hasEmptyRows() {
        const rows = this.container.querySelectorAll(this.rowSelector);
        const firstEmpty = [...rows].find(row => [...row.querySelectorAll('input')].filter(input => input.value).length === 0);
        return firstEmpty !== undefined;
    }

}