07_JS权威指南_03_零宽断言与负向先行断言.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8">
  </head>
  <body>
    <script>
    // console.log(/[^(]*/.exec('asdf (sadfasd')) // ["asdf ", index: 0, input: "asdf (sadfasd"]
    // console.log('abcdcd ef abcd'.match(/(ab|cd)+|ef/g)) // ["abcdcd", "ef", "abcd"]
    
    // (?=),零宽断言，(?=xxx) 后面必须有xxx，\ 转义
    console.log('abc:sdfabc'.match(/abc?(?=\:)/g)) // ["abc"]
    // (?!),负向先行断言，(?!xxx)后面不能有xxx。可以使用sublime编辑器 ctrl + f测试
    console.log('abcxxxdef'.match(/(abc|def)(?!xxx)/g))  // ["def"]
    </script>
  </body>
</html>