Regular Expressions: Escaping

Welcome to the Escaping lesson!

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In most programming languages, strings are delimited with "double quotes". To put a literal double quote in a string, we escape it. The string "\"" contains exactly one double quote. (It's the same as '"'.)
In regexes, + normally repeats whatever comes before it. But we can escape the + as \+ to match a literal "+". Likewise for other operators like ..

/\./.test('That is a cat.');

true

/\./.test('Is that a cat?');

false

>
/.\+./.test('111');
Result:
false
>
/.\+./.test('1+1');
Result:
true
>
/\++/.test('+');
Result:
true
>
/\++/.test('++');
Result:
true
>
/\+\+/.test('++');
Result:
true
>
/\+\+/.test('+');
Result:
false
Escaping can be used when you need a literal ^, $, etc. (It works for any operator.)
>
/\^/.test('^');
Result:
true
>
/\$/.test('$');
Result:
true
>
/\$$/.test('$a');
Result:
false
>
/\$$/.test('a$');
Result:
true
>
/a|b/.test('|');
Result:
false
>
/a\|b/.test('a|b');
Result:
true