indexOf ( 'nice', 3 ) != - 1 //false 'a nice string'. indexOf ( 'nice' ) != - 1 //true 'a nice string'. Like includes(), the second parameters sets the starting point: 'a nice string'. If the substring is found, it returns the index of the character that starts the string. includes ( searchvalue, start) Parameters Return Value More Examples Start at position 12: let text 'Hello world, welcome to the universe.' let result text. The includes () method is case sensitive. Pre-ES6, the common way to check if a string contains a substring was to use indexOf, which is a string method that return -1 if the string does not contain the substring. The includes () method returns true if a string contains a specified string. includes ( 'nice', 2 ) //true Pre-ES6 alternative to includes(): indexOf() includes ( 'nice', 3 ) //false 'a nice string'. includes ( 'nice' ) //true 'a nice string'.
Includes() also accepts an optional second parameter, an integer which indicates the position where to start searching for: 'a nice string'. To use it on all browsers, use Polyfill.io or another dedicated polyfill. It’s supported in all modern browsers except Internet Explorer: This method was introduced in ES6/ES2015.
The most simple one, and also the canonical one going forward, is using the includes() method on a string: 'a nice string'. JavaScript offers different ways to perform this operation. Learn the canonical way, and also find out all the options you have, using plain JavaScriptĬhecking if a string contains a substring is one of the most common tasks in any programming language. JavaScript offers many ways to check if a string contains a substring. log ( isASubstring ( "JavaScript", "Java" ) ) // true console. function isASubstring ( largerString, smallerString ) console. However, Internet Explorer and some other old browsersĭo not support the includes() method. Includes() method was introduced in ES6, since then it is a widely used string method. I am going to discuss two built-in methods of JavaScript string, which helps us in determining whether a string is a substring of another string or not. In this tutorial, you will learn how you can check whether a substring is included in a string or not.
0 kommentar(er)
