Remove Parenthesis from String in Javascript

Question

  x = x.replace(/[{()}]/g, '');
  y = y.replace(/[{()}]/g, '');

  x = x.replace(/[\[\]']+/g, '');
  y = y.replace(/[\[\]']+/g, '');

okay I understand that the first block removes the curly brackets, and the second block of code removes the regular brackets. I want to remove parenthesis now.. can someone show me how?

I've gotten the above code by just googling.. but I don't understand "how" they come up with this, can someone please explain? thanks

Answer 1

First Regex

x = x.replace(/[{()}]/g, '');
y = y.replace(/[{()}]/g, '');

In your first regex /[{()}]/g the outer square brackets [] makes a character class, it will match one of the character specified inside of it. In this case the characters { ( ) }.

Outside of the /regexp/ you have the g (global) modifier meaning that your entire regular expression will match as many times as it can , and it will not just make to the first match.

Second regex

x = x.replace(/[\[\]']+/g, '');
y = y.replace(/[\[\]']+/g, '');

In your second regex /[\[\]']+/g the outer square brackets [] makes a character class, it will match one of the character specified inside of it. In this case the characters [ ] '.

Note that the square brackets appear scaped inside the [character class] as \[ \].

After it you have specified a + quantifier, it makes the preceding rule match one or more times in a row. Note that this is redundant, even if it works, this is not quite what you want.

Outside of the /regularexpression/ you have the g (global) modifier meaning that your entire regular expression will match as many times as it can , and it will not just make to the first match.

---

Suggested Solution

run1.onclick = function() {
  //removes "(" and ")"
  output1.innerHTML = input1.value.replace(/[()]/g, ''); 
}

run2.onclick = function() {
  //removes (){}[]
  output2.innerHTML = input2.value.replace(/[\])}[{(]/g, ''); 
}

<p>Remove ()</p>
<input id="input1" type="text" value="(123) 1234-1234">
<input id="run1" type="button" value="run">
<span id="output1"></span>

<hr>

<p>Remove ()[]{}</p>
<input id="input2" type="text" value="Hello (this) is [] a {{test}}!">
<input id="run2" type="button" value="run">
<span id="output2"></span>