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JavaScript: Functional Programming for JavaScript Developers
book

JavaScript: Functional Programming for JavaScript Developers

by Ved Antani, Simon Timms, Dan Mantyla
August 2016
Intermediate to advanced
635 pages
14h 5m
English
Packt Publishing
Content preview from JavaScript: Functional Programming for JavaScript Developers

Backreferences

After an expression is evaluated, each group is stored for later use. These values are known as backreferences. Backreferences are created and numbered by the order in which opening parenthesis characters are encountered going from left to right. You can think of backreferences as the portions of a string that are successfully matched against terms in the regular expression.

The notation for a backreference is a backslash followed by the number of the capture to be referenced, beginning with 1, such as \1, \2, and so on.

An example could be /^([XYZ])a\1/, which matches a string that starts with any of the X, Y, or Z characters followed by an a and followed by whatever character matched the first capture. This is very different from ...

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Publisher Resources

ISBN: 9781787124660