获取与字符串名称同名的变量的值 [英] Get the value of a variable with with the same name as the value of a string

问题描述

我有一个jQuery窗口小部件，该窗口小部件在被调用时会输出一个目录.

I have a jQuery widget that outputs a table of contents when invoked.

我想让用户有机会在内容中指定每个独立元素的ID(默认为listElementID: 'contents-{index}')，因此我在小部件中提供了一个函数来实现此目的.

I'd like to give users the oppurtunity to specify the ID of each individal element within the contents (listElementID: 'contents-{index}' by default), so I've come up with a function within the widget to achieve this.

有很简单的条件-

1. 用传递给函数的index参数的值替换{index}.
2. 替换{.*}的其他实例(即{whatever}，并带有匹配的小部件选项this.options.whatever.

1. Replace {index} with the value of the index parameter that is passed to the function.
2. Replace and other instance of {.*} (I.e. {whatever} with the matching widget option this.options.whatever.

我可以从this.options.listElementID中提取所需的变量，但似乎找不到找到匹配参数/选项值的方法.

I can extract required variables from this.options.listElementID, but I can't seem to find a way to then get the value of the matching parameter/option.

我尝试使用eval()来做到这一点(对不起！)，但是例如，如果varName = 'index';，eval('varName');只是返回 index ，而不是index参数的值

I've tried to do this using eval() (sorry!), but if for example varName = 'index';, eval('varName'); simply returns index, not the value of the index parameter.

如何纠正我的代码?

_getContnetsLineID : function(index){

    var vars = (this.options.listElementID.match(/{.*}/g) || []),
        ID = this.options.listElementID;

    for(var i = 0; i < vars.length; i++){

        var varName,    // The name of the variable to grab the value from
            value;      // The value to replace the placehoder with

        varName = vars[i].replace('{', '').replace('}', '');    // Remove the '{' and '}' characters from the 'varName'

        if(varName == 'index'){ // Attempt to grab the value from a variable that matches the string 'varName'
            value = eval('varName');    
        } else {
            value = eval('this.options.varName');
        }

        ID = ID.replace(vars[i], value);    // Replace the placeholder with the appropriate value

    }

    return ID;

} // _getContnetsLineID

推荐答案

考虑:

this.options = {
    listElementID: "foobar-{index}-{whatever}",
    whatever: "hi"
};

_getLineID = function (index) {
    return this.options.listElementID.replace(/{(.+?)}/g, function (_, name) {
        return name === 'index' ? index : this.options[name];
    });
}

document.write(_getLineID(25));

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