打字稿lambda错误(Typescript lambda error)

打字稿lambda错误(Typescript lambda error)

我正在观看打字稿教程，有一点我必须编写这行代码

var squareItSimpler = function(h:number, w:number) => h * w;

但我无法让它发挥作用。 我一直在收到错误

The command "C:\Program Files (x86)\Microsoft SDKs\TypeScript\tsc.exe" --module AMD --target ES3....exited with code 1

而我只是不知道该怎么做，我在这里做错了什么？

有趣的是，这个休闲工作：

var squareItSimplest = (h:number, w:number) => h * w;

我正在使用TypeScript 0.9.0.1

I'm watching a typescript tutorial and at one point i have to write this line of code

var squareItSimpler = function(h:number, w:number) => h * w;

But i just can't get it to work. I keep getting the error

The command "C:\Program Files (x86)\Microsoft SDKs\TypeScript\tsc.exe" --module AMD --target ES3....exited with code 1

And i just don't know what to do, am i doing something wrong here ?

The funny this is that the fallowing works:

var squareItSimplest = (h:number, w:number) => h * w;

I'm using TypeScript 0.9.0.1

最满意答案

当您在Typescript中执行类似lambdas的操作时，请不要使用function关键字。 也许你的教程有错误。

编辑 - 从规范 ：

TypeScript支持箭头函数表达式，这是ECMAScript 6计划的新功能.Arow函数表达式是函数表达式的一种紧凑形式，它省略了function关键字并对此进行了词法作用域。

When you do lambdas like that in Typescript, you leave off the function keyword. Perhaps your tutorial has an error.

edit — from the spec:

TypeScript supports arrow function expressions, a new feature planned for ECMAScript 6. Arrow function expressions are a compact form of function expressions that omit the function keyword and have lexical scoping of this.