RegEx to find pattern “ JUNKCHARS” in Javascript string

Question

Consider below String,

var originalStr = "This is first string JUNKCHARS";

I need a regex to find a pattern " JUNKCHAR", ie characters JUNKCHAR with (any number of) whitespace before it and end of string after it.

e.g, 

// case 1
originalStr = "This is first string JUNKCHARS";

replacedStr = originalStr.replace(<pattern>, "");

console.log(replacedStr); // should output - This is first string

// case 2
originalStr = "This is first string            JUNKCHARS";

replacedStr = originalStr.replace(<pattern>, "");

console.log(replacedStr); // should output - This is first string

// case 3
originalStr = "This is first string JUNKCHARS    ";

replacedStr = originalStr.replace(<pattern>, "");

console.log(replacedStr); // should output - This is first string JUNKCHARS    

// case 4
originalStr = "This is first string JUNKCHARS test";

replacedStr = originalStr.replace(<pattern>, "");

console.log(replacedStr); // should output - This is first string JUNKCHARS test    

// case 5
originalStr = "This is first stringJUNKCHAR";

replacedStr = originalStr.replace(<pattern>, "");

console.log(replacedStr); // should output - This is first stringJUNKCHAR

// case 6
originalStr = "This is first string JUNKCHARtest";

replacedStr = originalStr.replace(<pattern>, "");

console.log(replacedStr); // should output - This is first string JUNKCHARtest

I have tried several regex but none seems to meet my requirement. Could anyone please help me in finding the right regex. Your help will be appreciated.

Answer 1

You may try something like this:

var text = 'This is first string JUNKCHARS    ';
text = text.replace(/\s{2,}JUNKCHARS/g,'').trim();
console.log(text);

Here is a demo: http://jqversion.com/#!/NYBiNrT

Answer 2

You can try something like this:

(?:^|\\s)(JUNKCHARS)(?=\\s|$)|\\sJUNKCHARS\\s

Answer 3

Let's go through that pattern by part

1. You want to match a number of whitespaces, but at least one, so that gives us \\s+
2. You want to match the string JUNKCHARS
3. You want the end of the string, which is $ in regex syntax

Together you'll get var pattern = /\\s+JUNKCHARS$/

You can fiddle around with it http://regex101.com/r/sU4eI3/1