Typescript String - Complete tutorials with examples

Learn Typescript String tutorials You can check other post on Fix for Object is possibly null

typescript String object Data type

The string contains a group of characters saved under the String object variable name. You need to know basic operations on String, How it works?

In this tutorial, we will walk through the different methods and examples.

Basic syntax Of String Object creation

var variable_name = new string('CloudHadoop')  

there are many ways we can create a string object in typescript

var cloudVariableName= new string('CloudHadoop');  
let newStringExample= '123';

a string is one of datatype in typescript.

Don’t confuse with the String object. The difference between string and String A string is a type in javascript and string is of typescript.

How to check The empty or Null of a String in typescript?

In this example, return true if String is Numeric.

String also contains numbers in single quotes.

To check String is Numeric, first, return the string format then check using isNaN method that checks for the valid number.

function checkSuppliedStringisNumeric(strParameter: string | number): boolean  
   return !isNaN(Number(strParameter.toString()));  
console.log(checkSuppliedStringisNumeric('123')) // outputs true  
console.log(checkSuppliedStringisNumeric('123abc')) // outputs false  
console.log(checkSuppliedStringisNumeric('abc')) // outputs false*+++  

How to remove whitespaces in String object?

This is the common requirement for deleting whitespaces from the String object.

It is easy to do in many ways. the string provides the trim()method which removes from first and last characters of a word, another way is using regular express which removes complete spaces.

console.log("cloud hadoop".replace(/\s/g, "")) // outputs cloudhadoop  
console.log("cloud hadoop".trim()) // outputs cloud hadoop  
console.log(" cloud hadoop ".replace(/\s/g, "")) // outputs cloudhadoop  
console.log(" cloud hadoop ".trim()) // outputs cloud hadoop  

String for each iteration Example

First, we will see how String array is created in typescript.

string type declared after variable followed by a semicolon.

iteration of strings achieved using forEach or for-in loop functionality

var msgs: string[] = ['string1', 'string2', 'string3'];  
var output;  
// _ForEach String array  iteration example_  
msgs.forEach(function(entry) {  
// _For-In String array iteration example  
_for(const msg in msgs) {  
// _For-Of String array iteration example  
_for (const m of msgs) {  
// _plain For loop String  array iteration example_  
for (let i = 0; i < msgs.length; ++i) {  
    console.log (msgs[i]);  

There are many ways to loop the String array. for-in and plain for loop using index mechanism to iterate elements and order not guaranteed.

whereas forEach and forOf iterates over each String array object.

typescript Split String into an array of Substrings example

Using the substring function, we can split a string using spaces

var message = "[cloud,hadoop,examples,tutorials]";  
function splitStringIntoArray(input) {  
 var messages = input.substring(1, input.length-1).split(", ");  
 return messages;  
document.body.innerHTML = splitStringIntoArray(message)[0] + " " + splitStringIntoArray(message)[1] + " " + splitmessages(message)[2];  

How to convert String to a Boolean example

strings contain true or false values. if we passed string the return of a Boolean value as a string, else return undefined.

Here undefined means not able to parse to a Boolean type

function transferToBoolean(input: string): boolean | undefined {  
    try {  
        return JSON.parse(input);  
    catch (e) {  
        return undefined;  
console.log(transferToBoolean("true")); // true  
console.log(transferToBoolean("false")); // false  
console.log(transferToBoolean("invalid")); // undefined  

String type methods

Typescript provides various inbuilt methods for manipulation of string content

Method Description
concat Joining the two strings and returning one output string
toLowerCase return the lowercase of output string
toUpperCase return the uppercase of the output string
toString returns the string content
substring returns the substring of starting index to end index
charAt return character at the specified index in a string
slice return the portion of a string

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To summarize, Learned string class in typescript with methods and example use cases.

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