Sure, here's how you can remove leading and trailing whitespaces from a string in TypeScript:
let str: string = " This is a string with leading and trailing whitespaces ";
// Removing leading whitespaces
str = str.replace(/^\s+/, '');
// Removing trailing whitespaces
str = str.replace(/\s+$/, '');
console.log(str); // "This is a string with leading and trailing whitespaces"
In the code above, we first declare a string variable str that contains leading and trailing whitespaces.
To remove the leading whitespaces, we use the replace() method with a regular expression (/^\s+/). Here, ^ matches the beginning of the string, \s matches any whitespace character, and + matches one or more occurrences of whitespace. We replace this pattern with an empty string '', effectively removing all leading whitespaces from the string.
Similarly, we remove the trailing whitespaces by using the replace() method with another regular expression (/\s+$/). Here, $ matches the end of the string, and we replace all trailing whitespaces with an empty string ''.
Finally, we log the modified string to the console.
Hope this helps! Let me know if you have any questions.