How to use the @pluginjs/dom.children function in @pluginjs/dom

children(this.$trigger).forEach(($this, i) => {
      const $content = children(this.$container)[i]

      removeClass(this.classes.SELECTED, $this)
      hideElement($content)
      this.leave(`${getData('type', $this)}Module`)
      if (getData('type', $this) === typeName) {
        addClass(this.classes.SELECTED, $this)
        $content.style.display = 'block'
        // showElement($content)
      }
    })

renderTree(node, isRoot, api) {
    let nodes

    if (isRoot) {
      nodes = node
      addClass(this.classes.TREE, node)
    } else {
      nodes = children('ul', node)[0]
    }

    if (nodes) {
      // has child
      addClass(this.classes.BRANCH, node)

      const privateIterate = tree => {
        children('li', tree).forEach(node => {
          const data = this.getBranch(node)
          const branchHtml = this.api.getBranchHtml(data)

          const div = query('div', node)
          if (div) {
            insertAfter(branchHtml, div)
            div.remove()
          } else {

initialize() {
    switch (this.type) {
      case 'root': {
        this.subelements = Array.from(this.dom.children)

        this.level = 0
        this.parent = null
        break
      }
      case 'branch':
      case 'leaf': {
        const childrenUl = children('ul', this.dom)
        if (childrenUl.length > 0) {
          this.subelements = Array.from(childrenUl[0].children)
        } else {
          this.subelements = []
        }

        this.$parent = parents(`.${this.classes.BRANCH}`, this.dom)[0]

        if (!this.$parent) {
          this.$parent = this.dom.parentNode
        }

        this.parent = getData('node', this.$parent)
        // this.parent = this.$parent.data('node')
        this.level = this.parent.level + 1
        break

attach(node, isRoot, api) {
    setData('node', new Node(node, isRoot, api), node)
    let childrenEl
    if (isRoot) {
      childrenEl = node
    } else {
      childrenEl = children('ul', node)[0]
    }

    if (childrenEl) {
      // has child
      const iterate = tree => {
        children('li', tree).forEach(node => {
          this.attach(node, false, api)
        })
      }
      iterate(childrenEl)
    }
  }

generateToggle() {
    if (isElement(this.options.toggle)) {
      this.$addon = this.options.toggle
      addClass(this.classes.ADDON, this.$addon)

      if (query(`.${this.classes.CHECK}`)) {
        this.$toggle = query(`.${this.classes.CHECK}`)
      }

      this.$toggle = children(this.$addon)[0]

      addClass(this.classes.TOGGLE, this.$toggle)
      insertAfter(this.$addon, this.element)
    } else if (this.options.toggle) {
      addClass(`${this.classes.HASICON}`, this.$wrap)
      this.$icon = parseHTML(
        template.render(this.options.templates.icon(), {
          classes: this.classes
        })
      )

      insertAfter(this.$icon, this.element)
    }
  }

getItems($parent) {
    return children($parent)
  },

delImage() {
    const target = children(this.$items)[this.indexed]

    if (target) {
      target.remove()
    }
  }

})
      }
      if (hasClass(this.classes.CLONED, prevItem)) {
        children(
          `.${this.classes.ITEM}:not(.${
            this.classes.CLONED
          })[data-swipe-item-index="${attr(
            'data-swipe-item-index',
            prevItem
          )}"]`,
          this.$inner
        ).forEach(children => {
          addClass(this.classes.CLONEDPREV, children)
        })
      } else {
        children(
          `.${this.classes.ITEM}.${
            this.classes.CLONED
          }[data-swipe-item-index="${attr(
            'data-swipe-item-index',
            prevItem
          )}"]`,
          this.$inner
        ).forEach(children => {
          addClass(this.classes.CLONEDPREV, children)
        })
      }
    }
  }

target: false,
        classes: {
          DROPDOWN: `${this.classes.DROPDOWN} {namespace}`
        },
        templates: {
          item() {
            return '<div class="{classes.ITEM}">{item.label}</div>'
          }
        },
        onSelect: el =&gt; {
          const index = getData('index', el)
          this.setActiveItem(this.$filters[index])
        }
      })
    } else {
      children(this.DROPDOWN.$dropdown).map(item =&gt; item.remove())
      this.DROPDOWN.appendItems(data)
    }

    this.setDropdownActive()
    this.trigger(EVENTS.RESPONSIVED)
  }