本文譯自 6 JavaScript Regular Expression features you can use today

正則表達(dá)式雖然非常強(qiáng)大，但眾所周知很難掌握。這里有 6 個(gè)有用的特性，可以幫助你開(kāi)始在你的 JavaScript 項(xiàng)目中使用它們：

捕獲組

捕獲組允許您獲取匹配字符串的特定部分，只需將部分正則表達(dá)式括在括號(hào)中即可 (...)：

const str = 'JavaScript is a programming language';
/(JavaScript) is a (.*)/.exec(str)
/*
  [
    0: 'JavaScript is a programming language',
    1: 'JavaScript',
    2: 'programming language'
    ...
  ]
*/

非捕獲組

非捕獲組用于匹配某些內(nèi)容而不捕獲它，例如您并不真正需要的一個(gè) / 或匹配組。它們的定義類似于捕獲組，但前綴為 ?:：

const str = 'JavaScript is a programming language';
/(?:JavaScript|Python) is a (.+)/.exec(str)
/*
  [
    0: 'JavaScript is a programming language',
    1: 'programming language'
    ...
  ]
*/

命名捕獲組

命名捕獲組允許您命名捕獲組，通過(guò)在它前面加上前綴 <name>：

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'
    }
    ...
  ]
*/

捕獲組反向引用

反向引用幫你寫(xiě)較短的正則表達(dá)式，通過(guò)重復(fù)現(xiàn)有的捕獲組，使用 \1，\2 等等。同樣地，你也可以重復(fù)命名捕捉使用群體 \k <name>：

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: {
      description: 'programming language'
    }
    ...
  ]
*/

前瞻

前瞻（Lookaheads）允許您檢查某些內(nèi)容是否遵循特定模式，而無(wú)需實(shí)際匹配它。您可以使用以下方法創(chuàng)建正先行斷言（?=）和負(fù)先行斷言（?!）：

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 字符

最后，您可以匹配 unicode 字符，使用 /p{...} 和 /u 標(biāo)志。示例包括但不限于 {Emoji}，{Math_Symbols} 和 {Script=Greek}：

const str = 'Greek looks like this: γεια';
/\p{Script=Greek}+/u.exec(str)
/*
  [
    0: 'γεια'
    ...
  ]
*/