In JavaScript, the typeof operator is the most used method to check the type of any variable. Alternatively, you can use the typeof() method: let myString = 'John Doe'; typeof myString; // string typeof(myString); // string If used with a string, the typeof operator returns "...
str3 = new String('Great Place'); Now to check whether a given variable is a string or not, we'll use a JavaScript operator calledtypeof. Syntax: typeof variable; This operator returns the data type of the variable specified after it. If the variable is of string data type, it will...
if(typeofmyVar==="string"){console.log("myVar is a string");}else{console.log("myVar is not a string");} Another way to check if a variable is a string is to use theinstanceofoperator, which returns true if an object is an instance of a particular constructor. For example, the ...
// Sample variable var myVar = 'Hello'; // Test if variable is a string if(typeof myVar === 'string') { alert('It is a string.'); } else { alert('It is not a string.'); }You can also define a custom function to check whether a variable is a string or not.The...
typeof check: if (typeof str === "string") Checks if str is of type "string", which applies to string literals. It does not return "string" for new String() because new String() is an object. Fallback: return "another type"; Handles cases where str is neither a string literal ...
Step 1: We have to find out if the given string is a palindrome or not. So to do this task we will create a function called isPalindrome and in this function, we will pass a parameter of string as str. So for this str, we will check the palindrome condition. Step 2: After the...
We can use search method to check if a string contains a substring or not as shown below. var actualstring = "Javascript search method", var substringToCheck = "search"; var isContains=actualstring.search("search") !== -1; //isContains true ...
Type.define = function(name, check, override){ var Type = this; if(!Type.isStr(name) || !Type.isFunc(check)){ throw new TypeError('Param error'); }else if(!override && this.__defined__[name]){ throw new Error('Type ' + name + ' already exists'); ...
Javascript Boolean Type Introduction Using the typeof operator, we can check the datatype of a variable. If the variable is a Boolean value, typeof will return the string 'boolean'. Copy vara =Boolean(true);varb = false;//www.java2s.comvarc ="";vard = newDate();if(typeofa ==='...
//写法一,单纯用===来判断(为啥addr为真,billAddr制表符和homeAddr空格符这两个为假呢?)console.log("写法一,单纯用===来判断");if(addr === "") { console.log("addr无值,为empty"); }else{ console.log("addr有值,不为empty,为" +addr); ...