javascript check if string code example

Example 1: is string javascript

function isString(value) {
	return typeof value === 'string' || value instanceof String;
}

isString(''); // true
isString(1); // false
isString({}); // false
isString([]); // false
isString(new String('teste')) // true

Example 2: if string javascript

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

Example 3: check for substring javascript

const string = "javascript";
const substring = "script";

console.log(string.includes(substring));  //true

Example 4: js test if string

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

Example 5: javascript is variable a string

if (typeof myVar === 'string'){
    //I am indeed a string
}

Example 6: js check if variable is string

if (typeof myVar === 'integer'){
    //I am indeed an integer
}

if (typeof myVar === 'boolean'){
    //I am indeed a boolean
}