正则扩展

正则新增特性

构造函数的变化 正则方法的扩展 u 修饰符 y 修饰符 s 修饰符

{
    // es5
    let regex = new RegExp("xyz", "i");
    let regex2 = new RegExp(/xyz/i);
    console.log(regex.test("xyz123"), regex2.test("xyz123")); // true true
    // es6
    let regex3 = new RegExp(/xyz/gi, "i");
    console.log(regex3.flags); // i
    // ES6为正则表达式新增了flags属性，会返回正则表达式的修饰符。
}
{
    let s = "bbb_bb_b";
    let a1 = /b+/g;
    let a2 = /b+/y;
    console.log("one", a1.exec(s), a2.exec(s));
    // one ["bbb", index: 0, input: "bbb_bb_b", groups: undefined]  ["bbb", index: 0, input: "bbb_bb_b", groups: undefined]
    console.log("two", a1.exec(s), a2.exec(s));
    // two ["bb", index: 4, input: "bbb_bb_b", groups: undefined] null
    console.log(a1.sticky, a2.sticky); // false true
}
{
    console.log("u-1", /^\uD83D/.test("\uD83D\uDC2A")); // u-1 true
    console.log("u-2", /^\uD83D/u.test("\uD83D\uDC2A")); // u-2 false
    console.log(/\u{61}/.test("a")); // false
    console.log(/\u{61}/u.test("a")); // true
    console.log(`\u{20BB7}`); // 𠮷
    let s = "𠮷";
    console.log("u-1", /^.$/.test(s)); // u-1 false
    console.log("u-2", /^.$/u.test(s)); // u-2 true
    console.log("test-1", /𠮷{2}/.test("𠮷𠮷")); // test-1 false
    console.log("test-2", /𠮷{2}/u.test("𠮷𠮷")); // test-2 true
}