how to check a string value in javascript code example

Example 1: javascript check if string contains a text substring

stringVariable.includes("Your Text");

Example 2: check if value is a string javascript

let eventValue = event.target.value;

    if (/^\d+$/.test(eventValue)) {
      eventValue = parseInt(eventValue, 10);
    }

//If value is a string, it converts to integer. 

//Otherwise it remains integer.