JavaScript treeview

treeview.js

const treeview = $('#treeviewCategories')
const categories = JSON.parse(serializeCategories.replace(/"/g, `"`))
const separatorCategory  = "-"
const urlProducts = "http://localhost:3000/Shop/Products/"
const initTag  = '<ul class="nested">'
const closeTag = '</ul>'

function expandSubcategories() {
    const subCategories = _getSubcategories()

    if (subCategories.length > 0) {
        const tags = _buildSubcategories(subCategories)
        $(this).parent().append(tags)
        $(".caret").click(expandSubcategories)
    } else {
        // get products by idCategory
        window.location = `${urlProducts}${idCategory}` 
    }
    
    $(this).parent().children("ul.nested").toggleClass("active")
    $(this).toggleClass("caret-down")
}

function _getSubcategories() {
    const idCategory    = $(this).parent().attr('id')                 
    const regexCategory = new RegExp("^" + idCategory + "-[0-9]+$")
    
    return categories.filter(category => category.path.search(regexCategory) !== -1)
}

function _buildSubcategories(subCategories) {
    return subCategories.reduce((acc, subCategory, index) => {
        if (subCategories.length === index++) {
            return acc + closeTag
        }
        return acc + `<li id="${subCategory.path}"><span class="caret">${subCategory.name}</span></li>`
    }, initTag)
}
  
// initial state collapsed tags
categories.forEach(category => {
    const paths = category.path.split(separatorCategory)

    if (paths.length === 1) {
        treeview.append(`<li id="${category.path}"><span class="caret">${category.name}</span></li>`)          
    } 
})

$(".caret").click(expandSubcategories)