TypeScript String substr() Method

The String.substr() method in TypeScript is an inbuilt function used to extract a portion of a string, starting at a specified index and extending for a given number of characters.

Syntax: 

string.substr(start[, length])

Parameter: This method accepts two parameters as mentioned above and described below.: 

• start - This parameter is the location at which to start extracting characters.
• length - This parameter is the number of characters to extract.

Return Value: This method returns the new sub-string. 

The below examples illustrate the String substr() method in TypeScript.

Example 1: Extracting a Substring from the Beginning

In this example we use substr() to extract a substring from str, starting at index 0 and spanning 5 characters.

let str: string = "GeeksforGeeks";
let result: string = str.substr(0, 5);

console.log(result);  // Output: Geeks

Output: 

Geeks

Example 2: Extracting a Substring from the Middle

In this example we use substr() to extract a substring from str, starting at index 5 and spanning 3 characters.

let str: string = "GeeksforGeeks";
let result: string = str.substr(5, 3);

console.log(result);  // Output: for

Output: 

for

Example 3: Extracting to the End of the String

In this example we use substr() to extract a substring from str, starting at index 8 and continuing to the end.

let str: string = "GeeksforGeeks";
let result: string = str.substr(8);

console.log(result);  // Output: Geeks

Output:

Geeks

Example 4: Extracting with Negative Start Index

In this example we use substr() to extract a substring from str, starting 5 characters from the end and spanning 4 characters.

let str: string = "GeeksforGeeks";
let result: string = str.substr(-5, 4);

console.log(result);  // Output: Geek

Output:

Geek