Fun with Unicode Regex

One of the problems in the chapter on Strings and Regular Expressions in Modern JavaScript for the Impatient is

Write a function that, given a string, produces an escaped string delimited by ’ characters. Turn all non-ASCII Unicode into \u{. . .}. Produce escapes \b, \f, \n, \r, \t, \v, ', \.

This was a pretty interesting thing to try. Working with Unicode in Regular Expressions is a little weird and it took me a while to figure out what would match non-ASCII Unicode and replace it with a encoding.

Here is what I came up with:

function escape(str) {
    str = str.replace(/\b/g, '\\b')
        .replace(/\f/g, '\\f')
        .replace(/\n/g, '\\n')
        .replace(/\r/g, '\\r')
        .replace(/\t/g, '\\t')
        .replace(/\v/g, '\\v')
        .replace(/\'/g, "\\'")
        .replace(/\\/g, '\\')
        .replace(/\p{S}/gu, (match) => {
        return '\\u{' +
            match.codePointAt(0).toString(16) +
            '}';
    });
    const quote = "'";
    return quote + str + quote;
}

There might be a more JavaScripty way to do it, but this seems to work. It’s not very elegant, but maybe I can improve it as I practice some more.

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