WebView无法正确缩放？(WebView not scaling correctly?)

 从MDN上的箭头功能文章： 
 
 
 
(param1, param2, …, paramN) => { statements }
(param1, param2, …, paramN) => expression
 
 
 您可以看到，无支撑语法要求箭头右侧的代码是一个表达式 ，这是语言本身所做的（不幸的） 区分 。 
 
 由于debugger是一种语句，因此在任何需要使用表达式的地方使用它都是语法错误。 有一件事你可以去解决这个问题，就是把你的调试器语句转换成一个表达式，然后你就可以把JavaScript当作评估对象而不是返回，例如： 
 
function debug(args) {
     debugger;
     return true;
}

params => debug() && params + 1

// or

params => console.log(params) || params + 1
 
 这样做的方式是因为逻辑运算符在JavaScript中的作用方式，这是真的： 
 
truthyA && B  === B

falsyA || B === B
 
 链接逻辑运算符时，JavaScript会从左到右评估子表达式，然后根据其布尔等效值进行操作。 这就是为什么你有时会看到&&用来代替if语句： 
 
 if (smth) doStuff();
 // is equivalent to:
 smth && doStuff();

From the MDN article on arrow functions:
 
 
 
(param1, param2, …, paramN) => { statements }
(param1, param2, …, paramN) => expression
 
 
You can see that the brace-less syntax requires the code on the right of the arrow to be an expression, which is an (unfortunate) distinction made by the language itself.
 
Since debugger is a statement, using it anywhere an expression is expected is a syntax error. One thing you could to to work around this is to transform your debugger statement in an expression which you trick JavaScript into evaluating but not returning, e.g.:
 
function debug(args) {
     debugger;
     return true;
}

params => debug() && params + 1

// or

params => console.log(params) || params + 1
 
The way this works is that because of the way logical operators function in JavaScript, this is true:
 
truthyA && B  === B

falsyA || B === B
 
When chaining logical operators, JavaScript evaluates sub-expressions left to right and then act depending on their boolean equivalent. That's why you'll sometimes see && used in place of if statements:
 
 if (smth) doStuff();
 // is equivalent to:
 smth && doStuff();