不打破缩进的多行字符串

问题描述：

根据此esdiscuss讨论，ECMAScript 6中可以定义多行字符串，而不需要将字符串的后续行放置在行的开始处。

According to this esdiscuss discussion, it is possible in ECMAScript 6 to define multiline strings without having to place subsequent lines of the string at the very beginning of the line.

Allen Wirfs-Brock的帖子包含代码示例：

var a = dontIndent
        `This is a template string.
         Even though each line is indented to keep the
         code neat and tidy, the white space used to indent
         is not in the resulting string`;

有人可以解释一下如何实现吗？如何定义这个 dontIndent 的东西，以便删除用于缩进的空格？

Could someone explain how this can be achieved? How to define this dontIndent thing in order to remove the whitespace used for indentation?

答

此功能通过定义自定义函数，然后将其作为标签（ dontIndent ）进行实现。代码打击来自 Zenparsing的要点：

This feature is implemented by defining a custom function and then using it as a tag (dontIndent above). The code blow is from Zenparsing's gist:

function dedent(callSite, ...args) {

    function format(str) {

        let size = -1;

        return str.replace(/\n(\s+)/g, (m, m1) => {

            if (size < 0)
                size = m1.replace(/\t/g, "    ").length;

            return "\n" + m1.slice(Math.min(m1.length, size));
        });
    }

    if (typeof callSite === "string")
        return format(callSite);

    if (typeof callSite === "function")
        return (...args) => format(callSite(...args));

    let output = callSite
        .slice(0, args.length + 1)
        .map((text, i) => (i === 0 ? "" : args[i - 1]) + text)
        .join("");

    return format(output);
}

我已经在Firefox中成功测试了它：

I've successfully tested it in Firefox Nightly:

不打破缩进的多行字符串

相关推荐