Understanding the 'endsWith()' Method in ES6 Strings

The 'endsWith()' method is a powerful tool provided by ES6, the sixth version of the ECMAScript language, which is a major component of JavaScript. This method helps to determine whether a string ends with a specific substring. In simple terms, it checks the ending characters of a string to see if they match a specified sequence of characters.

Working of the 'endsWith()' Method

As the correct answer in the quiz suggests, the 'endsWith()' method checks if a given string ends with the specified substring(s). This method accepts two parameters: the substring to search for and the length of the string to be searched (optional). If the second parameter is omitted, the full length of the string is considered.

var string = "Hello, world!";
console.log(string.endsWith("world!")); // Returns true
console.log(string.endsWith("Hello", 5)); // Returns true
console.log(string.endsWith("world?", 12)); // Returns false

In the above example, the first usage returns true because "world!" is found at the end of the string. The second usage also returns true because we're only checking the first five characters ("Hello"). The third usage returns false because "world?" is not found at the end when considering only the first 12 characters.

Practical Applications and Best Practices

The 'endsWith()' method is commonly used whenever there's a need to check the ending of a string. This could be while validating user inputs, parsing file formats (if a file name ends with .txt/.docx/.csv etc), or natural language processing tasks.

While using it, be aware that 'endsWith()' is case-sensitive and also considers any whitespace. Hence, ensure to manage the case conversion or trimming whitespaces based on the use-case.

Lastly, it's worth noting that 'endsWith()' does not change the original string. If you want to manipulate the string based on the result, you'll need to write additional code to do so.

Working with ES6 strings and especially with methods like 'endsWith()' provides robust solutions to string-related problems in a seamless and efficient way. Understanding these concepts can make work easier for anyone who frequently deals with strings in their JavaScript coding tasks.