You can add it to a script to dynamically load if needed.This is the official JavaScript string includes polyfil.Before you go an include the polyfil by default you should feature detect to determine if the script needs to be loaded.The key to detecting support is the first line of the polyfil:The first old school way to identify if a string or array contains a string is using the indexOf method. Learn how to search arrays and strings to determine if they contain your item. But like most modern APIs you should do feature detection in the browser to determine if a polyfil should be loaded. This works differently than the other methods because it returns an object representing the match.The match object includes the index where the match was found. String array we can use where we are not sure about kinds of data we will be stored at the run time. Definition and Usage. This works very differently than the other methods.Here you call test from the regular expression pattern and supply the source string. This works great for parsing data, a common business scenario.There are also multiple native regex methods to test for the presence of a string pattern.The search method works like the indexOf method. The only browser you need to worry about is Internet Explorer and old and deprecated NodeJs instances.

Ver también. We need not worry about the data type while using the JavaScript string array. By continuing, we'll assume you're cool with our cookie policy. Javascript indexOf method searches a specified item or string in the Given Array/String and returns its position. You have to write you own remove. Array.prototype.findIndex() – encuentra y devuelve un índice Array.prototype.includes() – comprueba que un valor existe en el array Array.prototype.filter() – elimina todos los elementos que no coincidan Array.prototype.every() – comprueba todos los elementos Array.prototype.some() – comprueba hasta que un elemento coincide If no match is found -1 is returned.The next method is match. La fuente de este ejemplo interactivo se almacena en un repositorio de GitHub. It returns the first position a match is found. For the most part this won't be an issue unless a user happens to be using Internet Explorer. It is a simple test.You can safely use the JavaScript includes method for both Arrays and Strings today. For String search it will returns the position of the first occurrence of a specified value in a string. It also includes the original test string or array.The interesting thing is when you modify the regular expression with the global modifier (g) the method returns an array of the matched values, not the full match object.The downside to using match is it only works on strings, not arrays.The last regular expression method is test. And since IE should only be limited to use with legacy web applications in enterprises the chances of encountering a browser not supporting includes is slim.The includes method only returns true or false is the criteria exists in the array or string. You can loop over the array, grab the index of the item you want to remove, and use splice to remove it. Alternatively, you can create a new array, loop over the current array, and if the current object doesn't match what you want to remove, put it in a new array. This is because arrays are zero indexed in JavaScript, so -1 means the value does not exist.The method returns true if the target string exists and false if it doesn't.The indexOf method is pretty basic, but not the most flexible technique. I presume you want to search an array of strings for any occurrence of the words in a specified string.

This means you need to have a polyfil available if your code uses this method.There are always polyfils available for modern functionality, well at least most of the time. Sintaxis str.search(expresionregular) Parámetros regexp Un objeto expresión regular.Si se pasa un objeto obj que no sea una expresión regular, se convierte implicitamente en una expresión regualar usando new RegExp(obj). If there is a match in the source string the method returns true. We should include the array of string in our routine as a developer to deal with the coding kinds of stuff. If the string or array contains the target string the method returns the first character index (string) or item index (Array) of the match.If there is no match found indexOf returns -1. I prefer using regular expressions because you can craft all sorts of patterns.The main advantage regular expressions have is they are not limited to a single string.

El índice de la primera coincidencia entre la expresión regular y la cadena de texto proporcionada, si no se encuentra devuelve Cuando se desee saber en qué casos un patrón se encuentra en una cadena de texto utiliza El siguiente ejemplo imprime un mensaje dependiendo de cuál sea el resultado de la evaluación.Get the latest and greatest from MDN delivered straight to your inbox.Por ahora, el boletín solo está disponible en inglés. Determining if a String or Array contains a sub string or set of characters using JavaScript is a common task. This method returns either true or false if the target string is contained within the source string or array.There is an optional fromIndex parameter you can add to indicate the first position the includes method should search.If a negative fromIndex value is supplied the source string or array is searched from position 0.For arrays, the search value must match an element, You can't match a substring of an element.The good news is browsers have good coverage of the JavaScript includes method. The find() method returns the value of the first element in an array that pass a test (provided as a function)..