JavaScript模板字符串,模板字符串有助于构建字符串,其功能类似于Perl或Python等其他语言中的字符串插值。
var name = "John";
var course = "Mathematics III";
var myString = `Hello ${name}, welcome to ${course}.`;
如示例所示,我们通过将变量名包含在${ … }
中来构建字符串。字符串将在运行时,用相关变量的当前值来构建。
注意,模板字符串必须包含在两个反单引号 而不是标准的单引号之间。这一要求带来的一个方便的副作用是,可以在字符串中使用引号而不需要再进行转义。
也可以替换较为复杂一些的表达式:
var total = 20;
var tax = 4;
msg = `Total is ${total} dollars (or ${total + tax} dollars, including tax)`;
alert(msg); // "Total is 20 dollars (or 24 dollars, including tax)"
模板字符串另一个很酷的作用是,它们能够扩展到多行。例如,可以编写如下代码:
var condition = "pressure";
var myString = `WARNING
The maximum safe ${condition} has been exceeded!`;
在运行时,该字符串将会被转换为:
"WARNING\n\nThe maximum safe pressure has been exceeded!"
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