javascript - 为什么允许独立代码块？

Question

我最近被 bug 咬了。我有这样的代码:

if (x == 1)
{
    do_stuff();
}
else
{
    do_other_stuff();
}

但是，我错误地省略了 else 这个词，所以第二个代码块总是被执行。

允许这样的独立代码块的理由是什么？我认为这是有充分理由的。

Answer 1

The block statement is often called compound statement in other languages. It allows you to use multiple statements where JavaScript expects only one statement. Combining statements into blocks is a common practice in JavaScript. The opposite behavior is possible using an empty statement, where you provide no statement, although one is required.

The block is delimited by a pair of curly brackets and may optionally be labelled (meaning it can be used with break or continue statements)

此外，它允许使用 let 或 const

block 范围变量

var x = 'Function scope'; {
  let x = 'Block Scope';
  console.log(x);
}

console.log(x);

引用:https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/block