javascript 如何将 switch 语句放入另一个 switch 语句中

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时间:2020-10-27 16:03:33  来源:igfitidea点击:

How to put a switch statement inside another switch statement

javascriptjqueryswitch-statement

提问by grabury

Im trying to work out a quote value after a user makes a selection in 2 select boxes.

在用户在 2 个选择框中进行选择后,我试图计算出报价值。

It looks like 1 need 2 switch statements. Is this possible? (There are a lot more possible values than the ones below. I've deleted them for the sake of clarity)

看起来 1 需要 2 个 switch 语句。这可能吗?(可能的值比下面的要多得多。为了清楚起见,我已经删除了它们)

 var workOutQuote = function() {
        var value1 = $("#delivery_from_area").val();
        var value2 = $("#delivery_to_area").val();
        var val = '';
            switch (value1)
            { case '1':
                { switch (value2)
                    { case '1': val="90"; break; }
                    { case '2': val="80"; break; }
                    { case '3': val="70"; break; }
                }
            }
            { case '2':
                { switch (value2)
                    { case '1': val="80"; break; }
                    { case '2': val="90"; break; }
                    { case '3': val="70"; break; }
                }
            }
}

Using the code above I get the error:

使用上面的代码我得到错误:

Uncaught SyntaxError: Unexpected token case 

回答by Prateek

Use BREAK, if you don't want to call all case. Otherwise ,you will get unexpected Results

使用BREAK,如果你don't want to call all case。否则,你会得到意想不到的结果

 var workOutQuote = function() {
        var value1 = $("#delivery_from_area").val();
        var value2 = $("#delivery_to_area").val();
        var val = '';
            switch (value1){ 
            case '1':
                 switch (value2){
                     case '1': val="90"; break; 
                     case '2': val="80"; break; 
                     case '3': val="70"; break; 
                }

            break;
            case '2':
                 switch (value2){
                     case '1': val="80"; break; 
                     case '2': val="90"; break; 
                     case '3': val="70"; break; 
                }
                break;             
}

回答by Bathsheba

The excessive use of braces is causing the statementafter the switch ()(that javascript grammar mandates you to include) to end early. Adjust to this:

大括号的过度使用导致(javascript 语法要求您包含)之后的语句switch ()提前结束。对此进行调整:

        switch (value1){
        case '1':
            switch (value2){
                case '1': val="90"; break;
                case '2': val="80"; break;
                case '3': val="70"; break;
            }
            break;            
        case '2':
            switch (value2){
                case '1': val="80"; break;
                case '2': val="90"; break;
                case '3': val="70"; break;
            }
            break;
       }

I've also taken the liberty of putting a break;between your outer cases since, at present your first case runs into the next one.

我也冒昧地break;在你的外壳之间放了一个,因为目前你的第一个案例会进入下一个案例。

The final breakI added (right at the bottom) is there for clarity: many folk would not include this.

break为了清楚起见,我添加的最后一个(在底部)是:很多人不会包括这个。

回答by Satpal

You are putting case in braces, an example from your code { case '1': val="90"; break; }

您正在放入案例braces,您的代码中的一个示例{ case '1': val="90"; break; }

    var value1 = '2';
    var value2 = '2';
    var val = '';
    switch (value1) {
        case '1':
            {
                switch (value2) {
                    case '1':
                        val = "90";
                        break;

                    case '2':
                        val = "80";
                        break;

                    case '3':
                        val = "70";
                        break;
                }
            }
        case '2':
            {
                switch (value2) {
                    case '1':
                        val = "80";
                        break;
                    case '2':
                        val = "90";
                        break;
                    case '3':
                        val = "70";
                        break;
                }
            }
    }

Demo

演示

回答by Rémi Benoit

Don't put brackets around each case :

不要在每个案例周围放置括号:

        switch (value1)
        { case '1':
            { switch (value2)
                { case '1': val="90"; break; }
                { case '2': val="80"; break; }

Should be :

应该 :

        switch (value1)
        { case '1':
            switch (value2) {
                 case '1': val="90"; break; 
                 case '2': val="80"; break; 
            }
        }