Answers for "how to find the element is string or not in js"

js test if string

if (typeof string === 'string') { /* code */ };

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.