![]() ![]() These would have a format such as this: 'filename.ext' To illustrate, let’s imagine that we wanted to replace import statements in a file with some other code. In the case of replace(), RegExes not only greatly enhances its search capabilities, but also allows us to capture substrings within matched content to examine – or even re-insert into – the matched substring in a different position. Today, they are implemented by many modern popular programming languages, including JavaScript. Regular expressions, or RegExes for short, are a dedicated pattern matching library dating all the way back to 1951. Read: Date Parsing Using JavaScript and Regular Expressions Matching by RegEx in JavaScript So, without further ado, let’s give these variations a try! It can also accept a regular expression (RegEx) search substring for more sophisticated matching as well as a replacer function so that the real signature looks more like this: let newStr = str.replace(substr: String | RegEx, newSubstr: String | Function) At least, that is how it behaves in its most basic form. Replace performs a substitution on the first match it finds. Notice that only the first instance of “rumble” was changed. outputs: "Can you hear the thunder? Can you hear the rumble that's calling?" Let newStr = source.replace("rumble", "thunder") Here is an example: let source = "Can you hear the rumble? Can you hear the rumble that's calling?" The replace() method returns a new string with a substring ( substr) replaced by a new one ( newSubstr), while leaving the invoking string unchanged. As such, the invoking object is the string to be searched, while the two arguments comprise the substring and replacement substring respectively: let newStr = str.replace(substr, newSubstr) Technically speaking, replace() is a public method of the String object. JavaScript replace(): One Function, Three Modes of Operation ![]() This JavaScript programming tutorial will provide an overview of JS’s Swiss army knife of functions and examples of its many uses. Although it only takes two arguments, this simple signature belies replace’s amazing versatility, as these can be of different types, depending on how exacting you need it to be. I soon found out that there is more to the replace() function than I was aware of. I thought I was too, until I had to use it recently. As a web developer, you are probably already familiar with JavaScript’s replace() function. Finding and replacing text is one of the oldest and most common tasks in programming, yet, it can still trip up novice and experienced coders alike. ![]()
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