Rename language articles

2023-05-18 23:57:15 +03:00
parent 45d1fa023a
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--- a/snippets/js/s/6-regexp-tricks.md
+++ b/snippets/js/s/6-regexp-tricks.md
@ -0,0 +1,121 @@
+---
+title: 6 JavaScript Regular Expression features you can use today
+shortTitle: JavaScript Regular Expression tips
+type: story
+language: javascript
+tags: [string,regexp]
+author: chalarangelo
+cover: taking-photos
+excerpt: Regular expressions are very powerful, but hard to master. Understand these features and start using them in your JavaScript code.
+dateModified: 2021-06-12T19:30:41+03:00
+---
+
+Regular expressions, while very powerful, are notoriously hard to master. Here are 6 useful features that can help you start using them in your JavaScript projects:
+
+### Capturing groups
+
+Capturing groups allow you to get specific parts of the matched string, simply by wrapping part of the regular expression in parentheses `(...)`:
+
+```js
+const str = 'JavaScript is a programming language';
+/(JavaScript) is a (.*)/.exec(str);
+/*
+  [
+    0: 'JavaScript is a programming language',
+    1: 'JavaScript',
+    2: 'programming language'
+  ]
+*/
+```
+
+### Non-capturing groups
+
+Non-capturing groups are used for matching something without capturing it, like an either/or matching group that you do not really need. They are defined similarly to capturing groups, but prefixed with `?:`:
+
+```js
+const str = 'JavaScript is a programming language';
+/(?:JavaScript|Python) is a (.+)/.exec(str);
+/*
+  [
+    0: 'JavaScript is a programming language',
+    1: 'programming language'
+  ]
+*/
+```
+
+### Named capturing groups
+
+Named capturing groups allow you to name a capturing group, by prefixing it with `<name>`:
+
+```js
+const str = 'JavaScript is a programming language';
+/(?<subject>.+) is a (?<description>.+)/.exec(str);
+/*
+  [
+    0: 'JavaScript is a programming language',
+    1: 'JavaScript',
+    2: 'programming language',
+    groups: {
+      subject: 'JavaScript,
+      description: 'programming language'
+    }
+  ]
+*/
+```
+
+### Capturing group backreferences
+
+Backreferences help you write shorter regular expressions, by repeating an existing capturing group, using `\1`, `\2` etc. Similarly, you can also repeat named capturing groups using `\k<name>`:
+
+```js
+const str = 'JavaScript is a programming language - an awesome programming language JavaScript is';
+/(.+) is a (?<description>.+) - an awesome \k<description> \1 is/.exec(str);
+/*
+  [
+    0: 'JavaScript is a programming language - an awesome programming language JavaScript is',
+    1: 'JavaScript',
+    2: 'programming language',
+    groups: {
+      subject: 'JavaScript,
+      description: 'programming language'
+    }
+  ]
+*/
+```
+
+### Lookaheads
+
+Lookaheads allow you to check if something is followed by a certain pattern, without actually matching it. You can create positive lookaheads using `?=` and negative lookaheads using `?!`:
+
+```js
+const str = 'JavaScript is not the same as Java and you should remember that';
+/Java(?=Script)(.*)/.exec(str);
+/*
+  [
+    0: 'JavaScript is not the same as Java and you should remember that',
+    1: 'Script is not the same as Java and you should remember that'
+  ]
+*/
+
+/Java(?!Script)(.*)/.exec(str);
+/*
+  [
+    0: 'Java and you should remember that',
+    1: ' and you should remember that'
+  ]
+*/
+```
+
+### Unicode characters
+
+Finally, you can match unicode characters, using `/p{...}` and the `/u` flag. Examples include, but are not limited to `{Emoji}`, `{Math_Symbols}` and `{Script=Greek}`:
+
+```js
+const str = 'Greek looks like this: γεια';
+/\p{Script=Greek}+/u.exec(str);
+/*
+  [
+    0: 'γεια'
+  ]
+*/
+```