javascript - 分割字符串之间的 JS if 语句

Question

如何在分割字符串之间放置 if 语句？显然我可以这样做:

if(lang == 'eng'){
  var a_string = 'hello';
}else if(lang == 'ger'){
  var a_string = 'hallo';
}

但这对于某些情况来说太长了。我想到的是以下内容:

var lang = (e.g. 'ger' or 'eng');

var a_string = 'h' + if(lang == 'eng'){'e'}else if(lang == 'ger'){'a'} + 'llo';

有没有办法在分割字符串之间编写 if 语句？

Answer 1

您可以使用conditional (ternary) operator :

The conditional (ternary) operator is the only JavaScript operator that takes three operands. This operator is frequently used as a shortcut for the if statement.

Syntax

condition ? expr1 : expr2 

var lang = 'eng';
document.write('h' + (lang == 'eng' ? 'e' : lang == 'ger' ? 'a' : '') + 'llo' + '<br>');
lang = 'ger';
document.write('h' + (lang == 'eng' ? 'e' : lang == 'ger' ? 'a' : '') + 'llo');

另一个解决方案 Logical AND (&&)和 Logical OR (||)可能是

var lang = 'eng';
document.write('h' + (lang == 'eng' && 'e' || lang == 'ger' && 'a' || '') + 'llo' + '<br>');
lang = 'ger';
document.write('h' + (lang == 'eng' && 'e' || lang == 'ger' && 'a' || '') + 'llo');