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@kangax
Last active August 29, 2015 13:57
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RegExp.escape(string)

Computes a new version of a String value in which certain characters have been escaped, so that the regular expression engine will interpret any metacharacters that it may contain as character literals.

When the escape function is called with one argument string, the following steps are taken:

  1. Let string be ToString(string).
  2. ReturnIfAbrupt(string).
  3. Let length be the number of characters in string.
  4. Let R be the empty string.
  5. Let k be 0.
  6. Repeat, while k < length, 1. Let C be the character at position k within string. 1. If C is one of the 16 nonblank characters "-[]{}()*+?.,\^$|" then,
    1. Let S be a String containing two characters "\x" where x is a C character. 1. Else,
    2. Let S be a String containing the single C character. 1. Let R be a new String value computed by concatenating the previous value of R and S. 1. Increase k by 1.
  7. Return R.
@cscott
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cscott commented May 22, 2014

@kangax re code unit, i think @inexorabletash was referring to step 3 and 6i. In particular, since regular expressions now have a "unicode" mode, you probably need to decide how you want to represent astral characters -- is that single "code point" encoded as two UTF-16 "code units" in an ordinary regexp, or as a single code point in a unicode mode regexp?

@rwaldron
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rwaldron commented Sep 8, 2014

@arv can you take a look at this?

@jdalton
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jdalton commented Feb 2, 2015

For reference here is lodash's implementation of lodash.escaperegexp.
The primary difference is it doesn't escape - or , because they fall out of escaping {} and [].
It also escapes / though I need to dig as to why it was added.

@zloirock
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@kangax any news about state of this proposal? I don't see it in this list, but it would be great to see it in ES7.

@benjamingr
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I made a repo here: https://github.com/benjamingr/RexExp.escape/blob/master/README.md any help would be appreciated.

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