In this article, we will see how to replace special characters in a string with an underscore in JavaScript. JavaScript replace() method is used to replace all special characters from a string with _ (underscore) which is described below:
JavaScript replace() Method: This method searches a string for a defined value, or a regular expression, and returns a new string with the replaced defined value.
Syntax:
string.replace(searchVal, newvalue)
Parameters:
- searchVal: It is a required parameter. It specifies the value or regular expression, that is going to replace by the new value.
- newvalue: It is a required parameter. It specifies the value to replace the search value with.
Return value: It returns a new string that matches the pattern specified in the parameters.
Example 1: This example replaces all special characters with _ (underscore) using replace() method.
Javascript
let str = "This, is# GeeksForGeeks!";console.log(str.replace(/[&\/\\#, +()$~%.'":*?<>{}]/g, '_')); |
This__is__GeeksForGeeks!
Example 2: This example replaces a unique special character with _ (underscore). This example goes to each character and checks if it is a special character that we are looking for, then it will replace the character. In this example, the unique character is $(dollar sign).
Javascript
let str = "A$computer$science$portal$for$Geeks";function gfg_Run() { let newStr = ""; for (let i = 0; i < str.length; i++) { if (str[i] == '$') { newStr += '_'; } else { newStr += str[i]; } } console.log(newStr);} gfg_Run(); |
A_computer_science_portal_for_Geeks
Example 3: In this example, we replace a unique special character with _ (underscore). This example spread function is used to form an array from a string and form a string with the help of reduce which excludes all special character and add underscore in their places. In this example the unique character are `&\/#, +()$~%.’”:*?<>{}`.
Javascript
let check = chr => `&\/#, +()$~%.'":*?<>{}`.includes(chr);let str = "This, is# GeeksForGeeks!";let underscore_str = [...str] .reduce((s, c) => check(c) ? s + '_' : s + c, '');console.log(underscore_str); |
This__is__GeeksForGeeks!
