拿来。 处理来自服务器的 500 个响应

Question

I send this request to the server:

fetch('/changeCountProductInCart', {
            method: 'POST',
            body: JSON.stringify({
                product_id: this.dataset.product_id,
                action: 'changeByInput',
                nodeName: this.nodeName,
                product_count: this.value
            }),
            headers: {
                'Accept': 'application/json',
                'Content-Type': 'application/json'
            }
        }).then(res => {
            if(res.ok) {
                totalAmount();
            } else if(!res.ok) {
                return res.json();
            }
        }).then(body => {
            this.value = body.stock;
        });

I want to go to then only if the response from the server only is not in the range of 200-300,but I just started to delve into promise and can't find the answer to my question

PS I will be grateful for any help or hint

Answer 1

You need to catch the server error responses:

fetch('/changeCountProductInCart', {
            method: 'POST',
            body: JSON.stringify({
                product_id: this.dataset.product_id,
                action: 'changeByInput',
                nodeName: this.nodeName,
                product_count: this.value
            }),
            headers: {
                'Accept': 'application/json',
                'Content-Type': 'application/json'
            }
        })
        .catch(err => /* error getting server response*/);