javascript 无法转换为对象

cannot convert to object

提问by dazz

if i execute the following code i get a cannot convert to object error; Uncaught exception: TypeError: Cannot convert 'validation.messages.field' to object

如果我执行以下代码，我会得到一个无法转换为对象的错误；未捕获的异常：TypeError：无法将“validation.messages.field”转换为对象

$.fn.validate = function(validation) {
    $.each(validation.rules, function(field, fieldRules){
        $.each(fieldRules, function(rule, ruleValue){
            var fieldValue = $('[name=' + field + ']').val();
            if (eval(rule + '(fieldValue, ruleValue)') == false){
                alert(validation.rules.field.rule);
                return false;
            }else{
                return true;
            };
        });
    });
}

the problem is the

问题是

alert(validation.messages.field.rule);

alert(validation.messages.field.rule);

'field' = 'persoon_voornaam' and 'rule' = 'required' and validation.messages.persoon_voornaam.requiredworks just fine.

'field' = 'persoon_voornaam' 和 'rule' = 'required' 并且validation.messages.persoon_voornaam.required工作得很好。

What am i doing wrong?

我究竟做错了什么？

validation is a JSON that look like this:

验证是一个如下所示的 JSON：

{
    rules: {
        persoon_voornaam: {
            required: true, 
            minlength: 5,
        },
        postcode_bestemming: {
            required: true, 
            minlength: 7,
        },
    },
    messages: {
        persoon_voornaam: {
            required: 'Dit veld is verplicht',
            minlengt: 'Dit veld moet minstens 5 lang zijn', 
        },
    }
}

采纳答案by Martin Jespersen

It has to be:

它一定要是：

alert(validation.rules[field][rule])

To clarify:

澄清：

validation.rulesis an object while fieldis a variable with the string 'persoon_voornaam'.

validation.rules是一个对象field而是一个带有字符串的变量'persoon_voornaam'。

validation.rules.persoon_voornaamis an object and the same as validation.rules['persoon_voornaam'].

validation.rules.persoon_voornaam是一个对象并且与 相同validation.rules['persoon_voornaam']。

回答by Felix Kling

The answer to your problem was already given. I want to propose an improved version of your code, to make your code more reusable (otherwise there is not need to attach it to the jQuery object).

你的问题已经给出了答案。我想提出您的代码的改进版本，以使您的代码更具可重用性（否则无需将其附加到 jQuery 对象）。

1. Your are not making use of the fact that this function will be applied to elements selected by your selector. You are selecting allform elements that match a certain name.
2. evalis evil. You would have to pollute the global namespace with functions named requiredand minlength.

1. 您没有利用此功能将应用于选择器选择的元素这一事实。您正在选择与某个名称匹配的所有表单元素。
2. eval是邪恶的。您将不得不使用名为requiredand 的函数污染全局命名空间minlength。

The following code tries to adress these issues:

以下代码试图解决这些问题：

$.fn.validate = (function() {
    var validators = {
        'required': function(value, ruleValue) {
             /*...*/
         },
         'minlength': function(value, ruleValue) {
            /*...*/
         }
    };

    return function(validation, config) {
        return this.each(function() {
            var errors = [];
            var $element = $(this);
            $.each(validation.rules, function(field, fieldRules){
                $.each(fieldRules, function(rule, ruleValue){
                    var fieldValue = $element.find('[name=' + field + ']').val();
                    if (rule in validators && validators[rule].call(null, fieldValue, ruleValue) === false){
                        var message = (field in validation.messages && rule in validation.messages[field]) ? validation.messages[field][rule] : '';
                        errors.push([field, rule, message])
                        return false;
                    }
                });
           });

           // the following part could be written shorter as 
           //  var cb = erros.length > 0 ? 'onerror' : 'onsuccess';
           //  if(typeof config[cb] === 'function') {
           //      config[cb](errors);
           //  }
           // but it will pass an empty array to success (which is not a problem
           // I just though it might be confusing)

           if(erros.length > 0) {
               if(typeof config.onerror === 'function') {
                   config.onerror(errors);
               }
           }
           else {
               if(typeof config.onsuccess === 'function') {
                   config.onsuccess();
               }
           }
       });
   }
}());

Then you can call the function with:

然后您可以使用以下命令调用该函数：

$('#yourFormId').validate(valditation, {
    onerror: function(errors) {
         // do something with errors
    },
    onsuccess: function() {
         // do something else
    }
});

and it will only validate the fields in the form.

它只会验证表单中的字段。