飞镖：从字符串创建方法 [英] Dart: Create method from string

问题描述

我一直在尝试使用Dart从字符串动态创建方法，但无济于事。字符串示例：（（String str）=> return str.length;。这个想法是允许用户创建自己的函数以应用于给定的字符串。我发现的唯一东西是NoSuchMethod，它似乎不适用于我的情况。我尝试在JavaScript中使用新函数，但是将函数传递给Dart并执行它时，出现以下错误： 未捕获的TypeError：J. $ index $ asx（...）。call $ 0不是函数 。

I've been trying to create methods dynamically from strings using Dart to no avail. String example: "(String str) => return str.length;". The idea is to allow users to create their own functions to apply to a given string. The only thing I've found is NoSuchMethod which does not seem to apply to my case. I tried using new Function in JavaScript but when passing the function to Dart and executing it, I get the following error: Uncaught TypeError: J.$index$asx(...).call$0 is not a function.

代码示例：

Dart：

context["UpdateNames"] =

(JsObject pTag)
{
    print(pTag["function"]("text"));
};

JS：

function execute ()
{
    var func = {"function": new Function("str", "return str.length;")};
    UpdateNames(func);
}

编辑：

解决方案：在JavaScript中创建一个这样的对象：

Solution: Create an object in JavaScript such as this:

this.fun = function (name)
  {
    var text = "var funs = " + document.getElementById("personalFun").value;
    eval(text);
    return funs(name);
  };

然后在Dart中创建对象：

Then create the object in Dart:

caller = new JsObject(context['Point'], []);

最后调用该方法以动态创建函数：

Finally call the method to dynamically create the function:

caller.callMethod('fun', [text]);

推荐答案

解决方案：在JavaScript中创建如下对象：

Solution: Create an object in JavaScript such as this:

var FunctionObject = function() {
  this.fun = function (name)
  {
    var text = "var funs = " + document.getElementById("personalFun").value;
    eval(text);
    return funs(name);
  };
};

然后在Dart中创建对象：

Then create the object in Dart:

caller = new JsObject(context['FunctionObject'], []);

最后调用该方法以动态创建函数：

Finally call the method to dynamically create the function:

caller.callMethod('fun', [text]);

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