UnitTestingDemo.js

if(orderTotal(
    {
        items:[
            {name: 'cat food', price: 10, quanity: 2},
            {name: 'cat bed', price: 20, quanity: 2},
            {name: 'shipping', price: 40, shipping: true}
          ]
    }
) !==100){
    throw new Error('quanity Path Fail')
}

if(orderTotal(
    {
        items:[
            {name: 'cat food', price: 10},
            {name: 'cat bed', price: 35},
            {name: 'shipping', price: 40, shipping: true}
          ]
    }
) !==85){
    throw new Error('main Path Fail')
}

if(orderTotal(
    {
        items:[
            {name: 'cat food', price: 10},
            {name: 'cat food', price: 10},
            {name: 'cat food', price: 10},
            {name: 'shipping', price: 40, shipping: true}
          ]
    }
) !==70){
    throw new Error('main Path Fail(2)')
}

if(orderTotal({
    items:[
        {name: 'cat food', price: 10},
        {name: 'cat bed', price: 40},
        {name: 'cat toy', price: 5},
        {name: 'shipping', price: 40, shipping: true}
      ]
}) !== 95) {
    throw new Error('Shipping less than 100')
}

if(orderTotal({
    items:[
        {name: 'cat food', price: 10},
        {name: 'cat bed', price: 40},
        {name: 'cat brush', price: 15},
        {name: 'cat pants', price: 30, quanity: 2},
        {name: 'shipping', price: 40, shipping: true}
      ]
}) !== 125) {
    throw new Error('Shipping less more than 100, free')
}



function orderTotal(order){
    const itemTotal = order.items
        .filter(item => !item.shipping)
        .reduce((prev, curr) => prev + curr.price * (curr.quanity || 1), 0)

        itemTotal

    const shippingItem = order.items
        .find(item => item.shipping) 

    shippingItem
    
    const shippingTotal = itemTotal > 100 ? 0 : shippingItem.price

    return itemTotal + shippingTotal

}