为什么在 if/else 语句之后不使用分号? [英] Why are semicolons not used after if/else statements?

问题描述

我知道在 Javascript 中的所有语句之后使用分号是一种很好的语法，但是有人知道为什么 if/else 语句在大括号之后不需要它们吗?

I understand that it is good syntax to use semicolons after all statements in Javascript, but does any one know why if/else statements do not require them after the curly braces?

推荐答案

• 分号用于结束 ONE 语句
• { 和 } 开始和关闭一组语句
• Semicolon is used to end ONE statement
• { and } begin and close a group of statements

基本上，if-else 后面必须跟一个语句或一组语句.

Basically, an if-else must be followed by either a statement or a group of statements.

if-else 后跟一个语句:

if (condition) statement;
if (condition); // followed by a statement (an empty statement)

if-else 后跟一组语句:

if (condition) {
   statement;
   statement;
}

if (condition) {
   // followed by a group of statements of zero length
}

if-else 必须以 ; 结尾，如果它后跟单个语句.if-else 后面跟着一组语句时不以 ; 结尾，因为 ; 用于结束单个语句，而不是用于结束一组语句.

if-else must end with a ; if it is followed by a single statement. if-else does not end with a ; when followed by a group of statements because ; is used to end a single statement, and is not used for ending a group of statements.

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