js 获取form 表单所有input

<form  action="javascript:;" onsubmit="return add_goods();" id="add_goods" method="post" enctype="multipart/form-data" >
    <div class="form-group">
        <label for="g_image">商品图片</label>
        <div class="input-group">
            <div class="custom-file">
                <input type="file" class="custom-file-input" name="g_image" id="g_image">
                <label class="custom-file-label" for="g_image">选择图片</label>
            </div>
            <div class="input-group-append">
                <span class="input-group-text">上传</span>
            </div>
        </div>
    </div>
</form>

function add_goods() {
        var _form = $('#add_goods');
        var data = _form.serializeArray(); // 批量获取input的字段
        console.log(data)
        //图片获取
        var files = $('#g_image')[0].files
        var formData = new FormData(); //新建⼀个formData对象
        formData.append("file", files[0]); //append()⽅法添加字段
        $.each(data, function(k, v) {
            formData.append(v.name,v.value)
        })

        $.ajax({
            url: "/admin/add_goods",
            data: formData,
            type: 'post',
            processData:false,//必填 必须false 才会避开jq对formdata的默认处理 XMLHttpRequest才会对formdata进⾏正确处理  否则会报Illegal invocation错误
            contentType:false,//必填 必须false 才会加上正确的Content-Type
            success: function (res) {
                console.log(res);
                var json = $.parseJSON(res)
                Swal.fire(json.msg)
            }})
    }