The Java String indexOf function is a method that returns the index of the first occurrence of a specified character or substring within a given string. It takes one or two arguments, the first being the character or substring to search for, and the second being an optional starting index from which to begin the search. If the character or substring is found, the method returns the index of its first occurrence within the string. If it is not found, the method returns -1. This function is useful for searching and manipulating strings in Java programs. Keep reading below to learn how to Java String indexOf in TypeScript.

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Java String indexOf in TypeScript With Example Code

Java developers who are transitioning to TypeScript may find themselves needing to use the Java String `indexOf` method in their TypeScript code. Fortunately, TypeScript provides a similar method that can be used in its place.

The TypeScript equivalent of the Java String `indexOf` method is the `indexOf` method of the `string` type. This method takes a single argument, which is the substring to search for within the string. It returns the index of the first occurrence of the substring within the string, or -1 if the substring is not found.

Here is an example of how to use the `indexOf` method in TypeScript:


const str: string = "Hello, world!";
const index: number = str.indexOf("world");
console.log(index); // Output: 7

In this example, we create a string variable `str` and assign it the value “Hello, world!”. We then call the `indexOf` method on `str`, passing in the substring “world”. The method returns the index of the first occurrence of “world” within `str`, which is 7. We then log the value of `index` to the console.

By using the `indexOf` method of the `string` type in TypeScript, Java developers can easily search for substrings within strings in their TypeScript code.

Equivalent of Java String indexOf in TypeScript

In conclusion, TypeScript provides a powerful and efficient way to work with strings in your code. The equivalent Java String indexOf function in TypeScript is the indexOf method, which allows you to search for a specific substring within a string and returns the index of the first occurrence. This method is easy to use and provides a lot of flexibility in terms of searching for substrings in your code. Whether you are a seasoned Java developer or new to TypeScript, the indexOf method is a great tool to have in your arsenal for working with strings. So, if you’re looking for a reliable and efficient way to search for substrings in your TypeScript code, be sure to give the indexOf method a try!

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