ECMAScript 6 入门教程—正则的扩展

/(?<=\$)\d+/.exec('Benjamin Franklin is on the $100 bill')  // ["100"]
/(?.exec('it’s is worth about €90')                // ["90"]

const RE_DOLLAR_PREFIX = /(?<=\$)foo/g;
'$foo %foo foo'.replace(RE_DOLLAR_PREFIX, 'bar');
// '$bar %foo foo'

/(?<=(\d+)(\d+))$/.exec('1053') // ["", "1", "053"]
/^(\d+)(\d+)$/.exec('1053') // ["1053", "105", "3"]

/(?<=(o)d\1)r/.exec('hodor')  // null
/(?<=\1d(o))r/.exec('hodor')  // ["r", "o"]

10、Unicode 属性类

const regexGreekSymbol = /\p{Script=Greek}/u;
regexGreekSymbol.test('π') // true

\p{UnicodePropertyName=UnicodePropertyValue}

\p{UnicodePropertyName}
\p{UnicodePropertyValue}

const regex = /^\p{Decimal_Number}+$/u;
regex.test('????????????????') // true

// 匹配所有数字
const regex = /^\p{Number}+$/u;
regex.test('²³¹¼½¾') // true
regex.test('㉛㉜㉝') // true
regex.test('ⅠⅡⅢⅣⅤⅥⅦⅧⅨⅩⅪⅫ') // true

// 匹配所有空格
\p{White_Space}

// 匹配各种文字的所有字母，等同于 Unicode 版的 \w
[\p{Alphabetic}\p{Mark}\p{Decimal_Number}\p{Connector_Punctuation}\p{Join_Control}]

// 匹配各种文字的所有非字母的字符，等同于 Unicode 版的 \W
[^\p{Alphabetic}\p{Mark}\p{Decimal_Number}\p{Connector_Punctuation}\p{Join_Control}]

// 匹配 Emoji
/\p{Emoji_Modifier_Base}\p{Emoji_Modifier}?|\p{Emoji_Presentation}|\p{Emoji}\uFE0F/gu

// 匹配所有的箭头字符
const regexArrows = /^\p{Block=Arrows}+$/u;
regexArrows.test('←↑→↓↔↕↖↗↘↙⇏⇐⇑⇒⇓⇔⇕⇖⇗⇘⇙⇧⇩') // true

11、具名组匹配

简介

const RE_DATE = /(\d{4})-(\d{2})-(\d{2})/;

const RE_DATE = /(\d{4})-(\d{2})-(\d{2})/;

const matchObj = RE_DATE.exec('1999-12-31');
const year = matchObj[1]; // 1999
const month = matchObj[2]; // 12
const day = matchObj[3]; // 31

const RE_DATE = /(?\d{4})-(?\d{2})-(?\d{2})/;

const matchObj = RE_DATE.exec('1999-12-31');
const year = matchObj.groups.year; // 1999
const month = matchObj.groups.month; // 12
const day = matchObj.groups.day; // 31

const RE_OPT_A = /^(?a+)?$/;
const matchObj = RE_OPT_A.exec('');

matchObj.groups.as // undefined
'as' in matchObj.groups // true

解构赋值和替换

let {groups: {one, two}} = /^(?<one>.*):(?<two>.*)$/u.exec('foo:bar');
one  // foo
two  // bar

let re = /(?<year>\d{4})-(?<month>\d{2})-(?<day>\d{2})/u;

'2015-01-02'.replace(re, '$/$/$')
// '02/01/2015'

'2015-01-02'.replace(re, (
   matched, // 整个匹配结果 2015-01-02
   capture1, // 第一个组匹配 2015
   capture2, // 第二个组匹配 01
   capture3, // 第三个组匹配 02
   position, // 匹配开始的位置 0
   S, // 原字符串 2015-01-02
   groups // 具名组构成的一个对象 {year, month, day}
 ) => {
 let {day, month, year} = groups;
 return `${day}/${month}/${year}`;
});

引用

const RE_TWICE = /^(?[a-z]+)!\k$/;
RE_TWICE.test('abc!abc') // true
RE_TWICE.test('abc!ab') // false

const RE_TWICE = /^(?[a-z]+)!\1$/;
RE_TWICE.test('abc!abc') // true
RE_TWICE.test('abc!ab') // false

const RE_TWICE = /^(?[a-z]+)!\k!\1$/;
RE_TWICE.test('abc!abc!abc') // true
RE_TWICE.test('abc!abc!ab') // false

正则匹配索引

const text = 'zabbcdef';
const re = /ab/;
const result = re.exec(text);

result.index // 1
result.indices // [ [1, 3] ]

const text = 'zabbcdef';
const re = /ab+(cd)/;
const result = re.exec(text);

result.indices // [ [ 1, 6 ], [ 4, 6 ] ]

const text = 'zabbcdef';
const re = /ab+(cd(ef))/;
const result = re.exec(text);

result.indices // [ [1, 8], [4, 8], [6, 8] ]

const text = 'zabbcdef';
const re = /ab+(?cd)/;
const result = re.exec(text);

result.indices.groups // { Z: [ 4, 6 ] }

const text = 'zabbcdef';
const re = /ab+(?ce)?/;
const result = re.exec(text);

result.indices[1] // undefined
result.indices.groups['Z'] // undefined

String.prototype.matchAll()

var regex = /t(e)(st(\d?))/g;
var string = 'test1test2test3';

var matches = [];
var match;
while (match = regex.exec(string)) {
  matches.push(match);
}

matches
// [
//   ["test1", "e", "st1", "1", index: 0, input: "test1test2test3"],
//   ["test2", "e", "st2", "2", index: 5, input: "test1test2test3"],
//   ["test3", "e", "st3", "3", index: 10, input: "test1test2test3"]
// ]

const string = 'test1test2test3';
const regex = /t(e)(st(\d?))/g;

for (const match of string.matchAll(regex)) {
  console.log(match);
}
// ["test1", "e", "st1", "1", index: 0, input: "test1test2test3"]
// ["test2", "e", "st2", "2", index: 5, input: "test1test2test3"]
// ["test3", "e", "st3", "3", index: 10, input: "test1test2test3"]

// 转为数组的方法一
[...string.matchAll(regex)]

// 转为数组的方法二
Array.from(string.matchAll(regex))