C#和JS交互之Microsoft.ClearScript.V8（V8引擎）

之前测试了很多JS引擎，都只支持es5语法，不支持执行es6，测试了下微软的V8反正能跑通，应该是支持的。还得是微软呀。

如图：安装相关包：

这是参考的官方V8代码

using Microsoft.ClearScript.JavaScript;
using Microsoft.ClearScript.V8;
using Microsoft.ClearScript;
using System.Security.Cryptography;

using (var engine = new V8ScriptEngine())

{

    // 指定JavaScript文件路径
    string filePath = @"D:\test\CallJS\CallJS\test.js";

    // 读取JavaScript文件内容

    string javascriptCode = File.ReadAllText(filePath);




    // expose a host type
    engine.Execute("var window = this;");

    engine.AddHostType("Console", typeof(Console));
    var type = "mp3";
    var mid = 440613;
    var para = $"corp=kuwo&p2p=1&type=convert_url2&sig=0&format={type}&rid={mid}";
    string str = "Console.WriteLine(encryptQuery('112233'))";
    string str1 = "Console.WriteLine(encryptQuery('para'))".Replace("para", para);
    engine.Execute(javascriptCode + C#有偿群：927860652);
    engine.Execute(javascriptCode + str1);
    engine.Execute("Console.WriteLine('{0} is an interesting number.', Math.PI)");



    // expose a host object

    engine.AddHostObject("random", new Random());

    engine.Execute("Console.WriteLine(random.NextDouble())");



    // expose entire assemblies

    engine.AddHostObject("lib", new HostTypeCollection("mscorlib", "System.Core"));

    engine.Execute("Console.WriteLine(lib.System.DateTime.Now)");



    // create a host object from script

    engine.Execute(@"
 
        birthday = new lib.System.DateTime(2007, 5, 22);
 
        Console.WriteLine(birthday.ToLongDateString());
 
    ");



    // use a generic class from script

    engine.Execute(@"
 
        Dictionary = lib.System.Collections.Generic.Dictionary;
 
        dict = new Dictionary(lib.System.String, lib.System.Int32);
 
        dict.Add('foo', 123);
 
    ");



    // call a host method with an output parameter

    engine.AddHostObject("host", new HostFunctions());

    engine.Execute(@"
 
        intVar = host.newVar(lib.System.Int32);
 
        found = dict.TryGetValue('foo', intVar.out);
 
        Console.WriteLine('{0} {1}', found, intVar);
 
    ");



    // create and populate a host array

    engine.Execute(@"
 
        numbers = host.newArr(lib.System.Int32, 20);
 
        for (var i = 0; i < numbers.Length; i++) { numbers[i] = i; }
 
        Console.WriteLine(lib.System.String.Join(', ', numbers));
 
    ");



    // create a script delegate

    engine.Execute(@"
 
        Filter = lib.System.Func(lib.System.Int32, lib.System.Boolean);
 
        oddFilter = new Filter(function(value) {
 
            return (value & 1) ? true : false;
 
        });
 
    ");



    // use LINQ from script

    engine.Execute(@"
 
        oddNumbers = numbers.Where(oddFilter);
 
        Console.WriteLine(lib.System.String.Join(', ', oddNumbers));
 
    ");



    // use a dynamic host object

    engine.Execute(@"
 
        expando = new lib.System.Dynamic.ExpandoObject();
 
        expando.foo = 123;
 
        expando.bar = 'qux';
 
        delete expando.foo;
 
    ");



    // call a script function

    engine.Execute("function print(x) { Console.WriteLine(x); }");

    engine.Script.print(DateTime.Now.DayOfWeek);



    // examine a script object

    engine.Execute("person = { name: 'Fred', age: 5 }");

    Console.WriteLine(engine.Script.person.name);



    // read a JavaScript typed array

    engine.Execute("values = new Int32Array([1, 2, 3, 4, 5])");

    var values = (ITypedArray<int>)engine.Script.values;

    Console.WriteLine(string.Join(", ", values.ToArray()));

}

稍微看下官网案例，就知道怎么用了。

再记录下es6转es5步骤：

1.npm执行以下命令：
npm install -g babel-cli 安装babel

2.查看版本 babel --version

3.初始化项目
执行npm init -y

4.安装转换包 npm install --save-dev babel-preset-es2015

5.转为新es5语法文件 babel src -d dist

记得把要转换的文件放在项目根目录，我把js文件放在根目录下的src文件夹中，然后创建.babelrc配置文件在根目录中
内容如下：

{"presets": ["es2015"],"plugins": []
}

然后会在根目录生成新的dist文件夹，es5版本的JS在里面。