ncatalin
3/8/2018 - 4:31 PM

Regular Expressions [Part 2] - Metacharacter Symbols

Modern JavaScript From The Beginning from Brad Traversy

index.html
content_copyfile_download
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>JavaScript Sandbox</title>
</head>
<body>
  
  <script src="app.js"></script>
</body>
</html>
app.js
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let re;
// Literal Characters
re = /hello/;
re = /hello/i;

// Metacharacter Symbols
re = /^h/i;           // Must start with
re = / world$/i;     // Must ends with
re = /^hello$/i;     // Must begin and end with
re = /h.llo/i;      // Matches any ONE character
re = /h*llo/i;      // Matches any character 0 or more times
re = /gre?a?y/i;    // Optional character
re = /gre?a?y\?/i;    // Escape character 


// String to match
const str = 'Gray?';


// Log Results
const result = re.exec(str);
console.log(result);

function reTest(re, str) {
  if(re.test(str)) {
    console.log(`${str} matches ${re.source}`);
  } else {
    console.log(`${str} does NOT match ${re.source}`);
  }
}

reTest(re, str);