regex read once bug

regex read once bug

read once bug

StackOverflow Question

https://stackoverflow.com/questions/59167961/regex-1-symbol-read-once-bug

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/n

https://regexper.com/#%2FMSIE ([0-9]{1%2C}[.0-9]{0%2C})%2F

IE

/MSIE ([0-9]{1,}[.0-9]{0,})/

Chrome canary version bug

OK & Version 78.0.3904.108 (Official Build) (64-bit)

Error & Chrome Canary Version 80.0.3982.0 (Official Build) canary (64-bit)

env

---

once bug

var e = 99;
var t = `MSIE 93`;
var ie = new RegExp("MSIE ([0-9]{1,}[.0-9]{0,})").exec(t);
ie != null && (e = parseFloat(RegExp.$1));
// 93

ie;
// (2) ["MSIE 93", "93", index: 0, input: "MSIE 93", groups: undefined]
RegExp.$1;
// "93"

var e = 99;
var t = `MSIE 93`;
var ie = new RegExp("MSIE ([0-9]{1,}[.0-9]{0,})").exec(t);
ie != null && (e = parseFloat(RegExp.$1));
// 93

ie;
// (2) ["MSIE 93", "93", index: 0, input: "MSIE 93", groups: undefined]
ie[0];
// "MSIE 93"
RegExp.$1;
// ""

testing

var e = 99;
var t = `MSIE 93`;
var ie = new RegExp("MSIE ([0-9]{1,}[.0-9]{0,})").exec(t);
ie != null && (e = parseFloat(RegExp.$1));
// 93

ie;
// (2) ["MSIE 93", "93", index: 0, input: "MSIE 93", groups: undefined]
ie[0];
// "MSIE 93"
RegExp.$1;
// " "

var e = 99;
var t = `MSIE 93`;
var ie = new RegExp("MSIE ([0-9]{1,}[.0-9]{0,})").exec(t);
ie != null && (e = parseFloat(RegExp.$1));
// 93

ie;
// (2) ["MSIE 93", "93", index: 0, input: "MSIE 93", groups: undefined]
RegExp.$1;
// "93"
RegExp.$1;
// ""

regex $1 Symbol read once bug

https://stackoverflow.com/questions/59167961/regex-1-symbol-read-once-bug

---

---

xgqfrms 2012-2020

www.cnblogs.com 发布文章使用：只允许注册用户才可以访问！

---