Typescript String - Complete tutorials with examples

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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 the datatypes in typescript.

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

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

In this example, return true if the String is Numeric.

String also contains numbers in single quotes.

To check String is Numeric, first, return the string format then check using the 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 the String array is created in typescript.

string type declared after the 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 iterate 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] +
  " " +

How to convert String to a Boolean example

strings contain true or false values. if we passed the 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 the manipulation of string content

concatJoining the two strings and returning one output string
toLowerCasereturn the lowercase of the output string
toUpperCasereturn the uppercase of the output string
toStringreturns the string content
substringreturns the substring of starting index to the end index
charAtreturn character at the specified index in a string
slicereturn the portion of a string

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