JAVASCRIPT

how to check if a string is in a string js

// Example 1:
const string = "Hello world!";

n = string.includes("world");

// n is equal to true in Example 1

// Example 2:
const string = "Hello world!, I am Kavyansh";

n = string.includes("I am Aman");
// n is equal to false in Example 2
// Note: the .includes method is case sensitive

if is a string javascript

function isString(x) {
  return Object.prototype.toString.call(x) === "[object String]"
}

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.

check if string javascript

it is better to check with isFinite() rather than typeof or isNAN() 
check this:
var name="somename",trickyName="123", invalidName="123abc";
typeof name == typeof trickyName == typeof invalidName == "string"
isNAN(name)==true
isNAN(trickyName)==false
isNAN(invalidName)==true
where:
isFinite(name) == false
isFinite(trickyName)== true
isFinite(invalidName)== true  
so we can do:
if(!isFinite(/*any string*/))
  console.log("it is string type for sure")
notice that:
	isFinite("asd123")==false
	isNAN("asd123")==true