Javascript Regex Negative Lookahead match

I suck at regex. I have the following expression:

(?!.*")(Level)(s)([0-9])(?!.*")

I want to use this expression to replace all Level 2 to "Level 2" with queries. The problem is that this regex catches "Level 2(without closing "). I want to catch Level 2 only if it has to quotes before AND after the words.

What is the best approach to do that?

asked Nov 20 '18 at 17:48

Filip

5512

Can you add some sample text and actual vs expected output with your current regex?

– Pushpesh Kumar Rajwanshi
Nov 20 '18 at 17:51

Try (?<=")levelsd+(?=")

– K.Dᴀᴠɪs
Nov 20 '18 at 17:52

I want to replace Excel Level 2 to Excel "Level 2" to refine some search results.

– Filip
Nov 20 '18 at 17:52

Try .replace(/"[^"]*"|b(Levels+d+)/g, (x,y) => y ? `"${y}"` : x )

– Wiktor Stribiżew
Nov 20 '18 at 17:52

@WiktorStribiżew not working. The callback is not called. Is this in the ES5?

– Filip
Nov 20 '18 at 17:56

|
show 3 more comments

I suck at regex. I have the following expression:

(?!.*")(Level)(s)([0-9])(?!.*")

What is the best approach to do that?

asked Nov 20 '18 at 17:48

Filip

5512

Can you add some sample text and actual vs expected output with your current regex?

– Pushpesh Kumar Rajwanshi
Nov 20 '18 at 17:51

Try (?<=")levelsd+(?=")

– K.Dᴀᴠɪs
Nov 20 '18 at 17:52

I want to replace Excel Level 2 to Excel "Level 2" to refine some search results.

– Filip
Nov 20 '18 at 17:52

Try .replace(/"[^"]*"|b(Levels+d+)/g, (x,y) => y ? `"${y}"` : x )

– Wiktor Stribiżew
Nov 20 '18 at 17:52

@WiktorStribiżew not working. The callback is not called. Is this in the ES5?

– Filip
Nov 20 '18 at 17:56

|
show 3 more comments

I suck at regex. I have the following expression:

(?!.*")(Level)(s)([0-9])(?!.*")

What is the best approach to do that?

asked Nov 20 '18 at 17:48

Filip

5512

I suck at regex. I have the following expression:

(?!.*")(Level)(s)([0-9])(?!.*")

What is the best approach to do that?

javascript regex

asked Nov 20 '18 at 17:48

Filip

5512

asked Nov 20 '18 at 17:48

Filip

5512

asked Nov 20 '18 at 17:48

Filip

5512

asked Nov 20 '18 at 17:48

Filip

5512

asked Nov 20 '18 at 17:48

Filip

5512

Can you add some sample text and actual vs expected output with your current regex?

– Pushpesh Kumar Rajwanshi
Nov 20 '18 at 17:51

Try (?<=")levelsd+(?=")

– K.Dᴀᴠɪs
Nov 20 '18 at 17:52

I want to replace Excel Level 2 to Excel "Level 2" to refine some search results.

– Filip
Nov 20 '18 at 17:52

Try .replace(/"[^"]*"|b(Levels+d+)/g, (x,y) => y ? `"${y}"` : x )

– Wiktor Stribiżew
Nov 20 '18 at 17:52

@WiktorStribiżew not working. The callback is not called. Is this in the ES5?

– Filip
Nov 20 '18 at 17:56

|
show 3 more comments

Can you add some sample text and actual vs expected output with your current regex?

– Pushpesh Kumar Rajwanshi
Nov 20 '18 at 17:51

Try (?<=")levelsd+(?=")

– K.Dᴀᴠɪs
Nov 20 '18 at 17:52

I want to replace Excel Level 2 to Excel "Level 2" to refine some search results.

– Filip
Nov 20 '18 at 17:52

Try .replace(/"[^"]*"|b(Levels+d+)/g, (x,y) => y ? `"${y}"` : x )

– Wiktor Stribiżew
Nov 20 '18 at 17:52

@WiktorStribiżew not working. The callback is not called. Is this in the ES5?

– Filip
Nov 20 '18 at 17:56

Can you add some sample text and actual vs expected output with your current regex?

– Pushpesh Kumar Rajwanshi
Nov 20 '18 at 17:51

Try (?<=")levelsd+(?=")

– K.Dᴀᴠɪs
Nov 20 '18 at 17:52

I want to replace Excel Level 2 to Excel "Level 2" to refine some search results.

– Filip
Nov 20 '18 at 17:52

Try .replace(/"[^"]*"|b(Levels+d+)/g, (x,y) => y ? `"${y}"` : x )

– Wiktor Stribiżew
Nov 20 '18 at 17:52

@WiktorStribiżew not working. The callback is not called. Is this in the ES5?

– Filip
Nov 20 '18 at 17:56

|
show 3 more comments

3 Answers
3

active

oldest

votes

You may use

var s = '"Level 3 protected": Level 4 here and "another Level 5"';

s = s.replace(/(^|[^"])(Levels+d+)(?!["d])/g, '$1"$2"');

console.log(s);

Details

(^|[^"]) - Group 1 ($1): start of string or any char but a double quote

(Levels+d+) - Group 2 ($2): Level, 1+ whitespaces, 1+ digits

(?!["d]) - no digit or double quote to the left of the current location is allowed.

See the regex demo.

answered Nov 20 '18 at 18:13

Wiktor Stribiżew

319k16139221

add a comment |

If you just want to capture every occurrence of Levels+d+ and replace it with "Levels+d+" provided it is not enclosed by doublequotes from both sides, you may use try using this regex,

([^"]|^)(Levels+d+)([^"]|$)

and replace it with,

1"2"3

Check here for a demo

This will not choose a text for replacement of type Label 2" or "Label 2 or "Label 2" and only replace when Label 2 when it is not surrounded by double quote from either side.

edited Nov 20 '18 at 19:23

answered Nov 20 '18 at 17:56

Pushpesh Kumar Rajwanshi

8,49021027

1

Not working ok, because it also replaces "Level 2" with ""Level 2"" regex101.com/r/kuTf1k/1

– Filip
Nov 20 '18 at 17:57

@Filip: Ok I've updated the answer to ensure it is not already surrounded by double quotes. Can you check now?

– Pushpesh Kumar Rajwanshi
Nov 20 '18 at 18:02

@PushpeshKumarRajwanshi You suggest something that only works with ECMAScript 2018 but even ES6 syntax does not work for OP.

– Wiktor Stribiżew
Nov 20 '18 at 18:04

oh ok Wiktor, sorry I forgot it was javascript where look behind doesn't work :( Let me figure out something else.

– Pushpesh Kumar Rajwanshi
Nov 20 '18 at 18:05

Yeah, I need something that works natively in browser as this is in a simple file not transpilled by babel.

– Filip
Nov 20 '18 at 18:08

|
show 3 more comments

^{Not sure if you want to replace "Level 2 and Level 2" or not, so I offer solutions for both scenarios:}

1) If you want to replace only those with not even a single ":

(?<!")(Levelsd+)(?!")

see https://regex101.com/r/Nc7b5h/1

This uses a negative look-behind and a negative look-ahead

2) However, if you also want to replace those with only one ", try this:

(?!"Levelsd+")(?<!")"?Levelsd+"?

https://regex101.com/r/qL5Li5/1/

Set your match group based on whether you want to replace the single " or not:

var s='This "Level 2" is "Level 2 a Level 2" test Level 2 :)'



s.replace(/(?!"Levelsd+")(?<!")"?(Levelsd+)"?/g, '"$1"');



//> 'This "Level 2" is "Level 2" a "Level 2" test "Level 2" :)'

var s='This "Level 2" is "Level 2 a Level 2" test Level 2 :)'



s.replace(/(?!"Levelsd+")(?<!")("?Levelsd+"?)/g, '"$1"');



//> 'This "Level 2" is ""Level 2" a "Level 2"" test "Level 2" :)'

The trick here was to first perform a negative look-ahead for the forbidden case of a match with two ", before doing anything else.

General Notes

If you don't want to use a look-behind expression ((?<!")) as older browsers (pre-ES2018) won't support that, just use (^|[^"]) instead, as other suggested. Just don't forget to restore its contents in the replacement :)

e.g. s.replace(/(?!"Levelsd+")(^|[^"])"?(Levelsd+)"?/g, '$1"$2"');

edited Nov 21 '18 at 8:32

answered Nov 20 '18 at 19:05

Jay

1,306511

1

Javascript does not support look behind.

– Rahul
Nov 20 '18 at 19:12

@Rahul Actually they are supported since ES 2018 :D

– Jay
Nov 20 '18 at 19:18

Is there an official release ?

– Rahul
Nov 20 '18 at 20:00

@Rahul ecma-international.org/ecma-262/9.0/#prod-Assertion

– Jay
Nov 20 '18 at 20:06

add a comment |

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3 Answers
3

active

oldest

votes

3 Answers
3

active

oldest

votes

You may use

var s = '"Level 3 protected": Level 4 here and "another Level 5"';

s = s.replace(/(^|[^"])(Levels+d+)(?!["d])/g, '$1"$2"');

console.log(s);

Details

(^|[^"]) - Group 1 ($1): start of string or any char but a double quote

(Levels+d+) - Group 2 ($2): Level, 1+ whitespaces, 1+ digits

(?!["d]) - no digit or double quote to the left of the current location is allowed.

See the regex demo.

answered Nov 20 '18 at 18:13

Wiktor Stribiżew

319k16139221

add a comment |

You may use

var s = '"Level 3 protected": Level 4 here and "another Level 5"';

s = s.replace(/(^|[^"])(Levels+d+)(?!["d])/g, '$1"$2"');

console.log(s);

Details

(^|[^"]) - Group 1 ($1): start of string or any char but a double quote

(Levels+d+) - Group 2 ($2): Level, 1+ whitespaces, 1+ digits

(?!["d]) - no digit or double quote to the left of the current location is allowed.

See the regex demo.

answered Nov 20 '18 at 18:13

Wiktor Stribiżew

319k16139221

add a comment |

You may use

var s = '"Level 3 protected": Level 4 here and "another Level 5"';

s = s.replace(/(^|[^"])(Levels+d+)(?!["d])/g, '$1"$2"');

console.log(s);

Details

(^|[^"]) - Group 1 ($1): start of string or any char but a double quote

(Levels+d+) - Group 2 ($2): Level, 1+ whitespaces, 1+ digits

(?!["d]) - no digit or double quote to the left of the current location is allowed.

See the regex demo.

answered Nov 20 '18 at 18:13

Wiktor Stribiżew

319k16139221

You may use

var s = '"Level 3 protected": Level 4 here and "another Level 5"';

s = s.replace(/(^|[^"])(Levels+d+)(?!["d])/g, '$1"$2"');

console.log(s);

Details

(^|[^"]) - Group 1 ($1): start of string or any char but a double quote

(Levels+d+) - Group 2 ($2): Level, 1+ whitespaces, 1+ digits

(?!["d]) - no digit or double quote to the left of the current location is allowed.

See the regex demo.

var s = '"Level 3 protected": Level 4 here and "another Level 5"';

s = s.replace(/(^|[^"])(Levels+d+)(?!["d])/g, '$1"$2"');

console.log(s);

var s = '"Level 3 protected": Level 4 here and "another Level 5"';

s = s.replace(/(^|[^"])(Levels+d+)(?!["d])/g, '$1"$2"');

console.log(s);

answered Nov 20 '18 at 18:13

Wiktor Stribiżew

319k16139221

answered Nov 20 '18 at 18:13

Wiktor Stribiżew

319k16139221

answered Nov 20 '18 at 18:13

Wiktor Stribiżew

319k16139221

answered Nov 20 '18 at 18:13

Wiktor Stribiżew

319k16139221

add a comment |

If you just want to capture every occurrence of Levels+d+ and replace it with "Levels+d+" provided it is not enclosed by doublequotes from both sides, you may use try using this regex,

([^"]|^)(Levels+d+)([^"]|$)

and replace it with,

1"2"3

Check here for a demo

This will not choose a text for replacement of type Label 2" or "Label 2 or "Label 2" and only replace when Label 2 when it is not surrounded by double quote from either side.

edited Nov 20 '18 at 19:23

answered Nov 20 '18 at 17:56

Pushpesh Kumar Rajwanshi

8,49021027

1

Not working ok, because it also replaces "Level 2" with ""Level 2"" regex101.com/r/kuTf1k/1

– Filip
Nov 20 '18 at 17:57

@Filip: Ok I've updated the answer to ensure it is not already surrounded by double quotes. Can you check now?

– Pushpesh Kumar Rajwanshi
Nov 20 '18 at 18:02

@PushpeshKumarRajwanshi You suggest something that only works with ECMAScript 2018 but even ES6 syntax does not work for OP.

– Wiktor Stribiżew
Nov 20 '18 at 18:04

oh ok Wiktor, sorry I forgot it was javascript where look behind doesn't work :( Let me figure out something else.

– Pushpesh Kumar Rajwanshi
Nov 20 '18 at 18:05

Yeah, I need something that works natively in browser as this is in a simple file not transpilled by babel.

– Filip
Nov 20 '18 at 18:08

|
show 3 more comments

If you just want to capture every occurrence of Levels+d+ and replace it with "Levels+d+" provided it is not enclosed by doublequotes from both sides, you may use try using this regex,

([^"]|^)(Levels+d+)([^"]|$)

and replace it with,

1"2"3

Check here for a demo

This will not choose a text for replacement of type Label 2" or "Label 2 or "Label 2" and only replace when Label 2 when it is not surrounded by double quote from either side.

edited Nov 20 '18 at 19:23

answered Nov 20 '18 at 17:56

Pushpesh Kumar Rajwanshi

8,49021027

1

Not working ok, because it also replaces "Level 2" with ""Level 2"" regex101.com/r/kuTf1k/1

– Filip
Nov 20 '18 at 17:57

@Filip: Ok I've updated the answer to ensure it is not already surrounded by double quotes. Can you check now?

– Pushpesh Kumar Rajwanshi
Nov 20 '18 at 18:02

@PushpeshKumarRajwanshi You suggest something that only works with ECMAScript 2018 but even ES6 syntax does not work for OP.

– Wiktor Stribiżew
Nov 20 '18 at 18:04

oh ok Wiktor, sorry I forgot it was javascript where look behind doesn't work :( Let me figure out something else.

– Pushpesh Kumar Rajwanshi
Nov 20 '18 at 18:05

Yeah, I need something that works natively in browser as this is in a simple file not transpilled by babel.

– Filip
Nov 20 '18 at 18:08

|
show 3 more comments

If you just want to capture every occurrence of Levels+d+ and replace it with "Levels+d+" provided it is not enclosed by doublequotes from both sides, you may use try using this regex,

([^"]|^)(Levels+d+)([^"]|$)

and replace it with,

1"2"3

Check here for a demo

This will not choose a text for replacement of type Label 2" or "Label 2 or "Label 2" and only replace when Label 2 when it is not surrounded by double quote from either side.

edited Nov 20 '18 at 19:23

answered Nov 20 '18 at 17:56

Pushpesh Kumar Rajwanshi

8,49021027

If you just want to capture every occurrence of Levels+d+ and replace it with "Levels+d+" provided it is not enclosed by doublequotes from both sides, you may use try using this regex,

([^"]|^)(Levels+d+)([^"]|$)

and replace it with,

1"2"3

Check here for a demo

This will not choose a text for replacement of type Label 2" or "Label 2 or "Label 2" and only replace when Label 2 when it is not surrounded by double quote from either side.

edited Nov 20 '18 at 19:23

answered Nov 20 '18 at 17:56

Pushpesh Kumar Rajwanshi

8,49021027

edited Nov 20 '18 at 19:23

answered Nov 20 '18 at 17:56

Pushpesh Kumar Rajwanshi

8,49021027

answered Nov 20 '18 at 17:56

Pushpesh Kumar Rajwanshi

8,49021027

answered Nov 20 '18 at 17:56

Pushpesh Kumar Rajwanshi

8,49021027

1

Not working ok, because it also replaces "Level 2" with ""Level 2"" regex101.com/r/kuTf1k/1

– Filip
Nov 20 '18 at 17:57

@Filip: Ok I've updated the answer to ensure it is not already surrounded by double quotes. Can you check now?

– Pushpesh Kumar Rajwanshi
Nov 20 '18 at 18:02

@PushpeshKumarRajwanshi You suggest something that only works with ECMAScript 2018 but even ES6 syntax does not work for OP.

– Wiktor Stribiżew
Nov 20 '18 at 18:04

oh ok Wiktor, sorry I forgot it was javascript where look behind doesn't work :( Let me figure out something else.

– Pushpesh Kumar Rajwanshi
Nov 20 '18 at 18:05

Yeah, I need something that works natively in browser as this is in a simple file not transpilled by babel.

– Filip
Nov 20 '18 at 18:08

|
show 3 more comments

1

Not working ok, because it also replaces "Level 2" with ""Level 2"" regex101.com/r/kuTf1k/1

– Filip
Nov 20 '18 at 17:57

@Filip: Ok I've updated the answer to ensure it is not already surrounded by double quotes. Can you check now?

– Pushpesh Kumar Rajwanshi
Nov 20 '18 at 18:02

@PushpeshKumarRajwanshi You suggest something that only works with ECMAScript 2018 but even ES6 syntax does not work for OP.

– Wiktor Stribiżew
Nov 20 '18 at 18:04

oh ok Wiktor, sorry I forgot it was javascript where look behind doesn't work :( Let me figure out something else.

– Pushpesh Kumar Rajwanshi
Nov 20 '18 at 18:05

Yeah, I need something that works natively in browser as this is in a simple file not transpilled by babel.

– Filip
Nov 20 '18 at 18:08

Not working ok, because it also replaces "Level 2" with ""Level 2"" regex101.com/r/kuTf1k/1

– Filip
Nov 20 '18 at 17:57

@Filip: Ok I've updated the answer to ensure it is not already surrounded by double quotes. Can you check now?

– Pushpesh Kumar Rajwanshi
Nov 20 '18 at 18:02

@PushpeshKumarRajwanshi You suggest something that only works with ECMAScript 2018 but even ES6 syntax does not work for OP.

– Wiktor Stribiżew
Nov 20 '18 at 18:04

oh ok Wiktor, sorry I forgot it was javascript where look behind doesn't work :( Let me figure out something else.

– Pushpesh Kumar Rajwanshi
Nov 20 '18 at 18:05

Yeah, I need something that works natively in browser as this is in a simple file not transpilled by babel.

– Filip
Nov 20 '18 at 18:08

|
show 3 more comments

^{Not sure if you want to replace "Level 2 and Level 2" or not, so I offer solutions for both scenarios:}

1) If you want to replace only those with not even a single ":

(?<!")(Levelsd+)(?!")

see https://regex101.com/r/Nc7b5h/1

This uses a negative look-behind and a negative look-ahead

2) However, if you also want to replace those with only one ", try this:

(?!"Levelsd+")(?<!")"?Levelsd+"?

https://regex101.com/r/qL5Li5/1/

Set your match group based on whether you want to replace the single " or not:

var s='This "Level 2" is "Level 2 a Level 2" test Level 2 :)'



s.replace(/(?!"Levelsd+")(?<!")"?(Levelsd+)"?/g, '"$1"');



//> 'This "Level 2" is "Level 2" a "Level 2" test "Level 2" :)'

var s='This "Level 2" is "Level 2 a Level 2" test Level 2 :)'



s.replace(/(?!"Levelsd+")(?<!")("?Levelsd+"?)/g, '"$1"');



//> 'This "Level 2" is ""Level 2" a "Level 2"" test "Level 2" :)'

The trick here was to first perform a negative look-ahead for the forbidden case of a match with two ", before doing anything else.

General Notes

e.g. s.replace(/(?!"Levelsd+")(^|[^"])"?(Levelsd+)"?/g, '$1"$2"');

edited Nov 21 '18 at 8:32

answered Nov 20 '18 at 19:05

Jay

1,306511

1

Javascript does not support look behind.

– Rahul
Nov 20 '18 at 19:12

@Rahul Actually they are supported since ES 2018 :D

– Jay
Nov 20 '18 at 19:18

Is there an official release ?

– Rahul
Nov 20 '18 at 20:00

@Rahul ecma-international.org/ecma-262/9.0/#prod-Assertion

– Jay
Nov 20 '18 at 20:06

add a comment |

^{Not sure if you want to replace "Level 2 and Level 2" or not, so I offer solutions for both scenarios:}

1) If you want to replace only those with not even a single ":

(?<!")(Levelsd+)(?!")

see https://regex101.com/r/Nc7b5h/1

This uses a negative look-behind and a negative look-ahead

2) However, if you also want to replace those with only one ", try this:

(?!"Levelsd+")(?<!")"?Levelsd+"?

https://regex101.com/r/qL5Li5/1/

Set your match group based on whether you want to replace the single " or not:

var s='This "Level 2" is "Level 2 a Level 2" test Level 2 :)'



s.replace(/(?!"Levelsd+")(?<!")"?(Levelsd+)"?/g, '"$1"');



//> 'This "Level 2" is "Level 2" a "Level 2" test "Level 2" :)'

var s='This "Level 2" is "Level 2 a Level 2" test Level 2 :)'



s.replace(/(?!"Levelsd+")(?<!")("?Levelsd+"?)/g, '"$1"');



//> 'This "Level 2" is ""Level 2" a "Level 2"" test "Level 2" :)'

The trick here was to first perform a negative look-ahead for the forbidden case of a match with two ", before doing anything else.

General Notes

e.g. s.replace(/(?!"Levelsd+")(^|[^"])"?(Levelsd+)"?/g, '$1"$2"');

edited Nov 21 '18 at 8:32

answered Nov 20 '18 at 19:05

Jay

1,306511

1

Javascript does not support look behind.

– Rahul
Nov 20 '18 at 19:12

@Rahul Actually they are supported since ES 2018 :D

– Jay
Nov 20 '18 at 19:18

Is there an official release ?

– Rahul
Nov 20 '18 at 20:00

@Rahul ecma-international.org/ecma-262/9.0/#prod-Assertion

– Jay
Nov 20 '18 at 20:06

add a comment |

^{Not sure if you want to replace "Level 2 and Level 2" or not, so I offer solutions for both scenarios:}

1) If you want to replace only those with not even a single ":

(?<!")(Levelsd+)(?!")

see https://regex101.com/r/Nc7b5h/1

This uses a negative look-behind and a negative look-ahead

2) However, if you also want to replace those with only one ", try this:

(?!"Levelsd+")(?<!")"?Levelsd+"?

https://regex101.com/r/qL5Li5/1/

Set your match group based on whether you want to replace the single " or not:

var s='This "Level 2" is "Level 2 a Level 2" test Level 2 :)'



s.replace(/(?!"Levelsd+")(?<!")"?(Levelsd+)"?/g, '"$1"');



//> 'This "Level 2" is "Level 2" a "Level 2" test "Level 2" :)'

var s='This "Level 2" is "Level 2 a Level 2" test Level 2 :)'



s.replace(/(?!"Levelsd+")(?<!")("?Levelsd+"?)/g, '"$1"');



//> 'This "Level 2" is ""Level 2" a "Level 2"" test "Level 2" :)'

The trick here was to first perform a negative look-ahead for the forbidden case of a match with two ", before doing anything else.

General Notes

e.g. s.replace(/(?!"Levelsd+")(^|[^"])"?(Levelsd+)"?/g, '$1"$2"');

edited Nov 21 '18 at 8:32

answered Nov 20 '18 at 19:05

Jay

1,306511

^{Not sure if you want to replace "Level 2 and Level 2" or not, so I offer solutions for both scenarios:}

1) If you want to replace only those with not even a single ":

(?<!")(Levelsd+)(?!")

see https://regex101.com/r/Nc7b5h/1

This uses a negative look-behind and a negative look-ahead

2) However, if you also want to replace those with only one ", try this:

(?!"Levelsd+")(?<!")"?Levelsd+"?

https://regex101.com/r/qL5Li5/1/

Set your match group based on whether you want to replace the single " or not:

var s='This "Level 2" is "Level 2 a Level 2" test Level 2 :)'



s.replace(/(?!"Levelsd+")(?<!")"?(Levelsd+)"?/g, '"$1"');



//> 'This "Level 2" is "Level 2" a "Level 2" test "Level 2" :)'

var s='This "Level 2" is "Level 2 a Level 2" test Level 2 :)'



s.replace(/(?!"Levelsd+")(?<!")("?Levelsd+"?)/g, '"$1"');



//> 'This "Level 2" is ""Level 2" a "Level 2"" test "Level 2" :)'

The trick here was to first perform a negative look-ahead for the forbidden case of a match with two ", before doing anything else.

General Notes

e.g. s.replace(/(?!"Levelsd+")(^|[^"])"?(Levelsd+)"?/g, '$1"$2"');

edited Nov 21 '18 at 8:32

answered Nov 20 '18 at 19:05

Jay

1,306511

edited Nov 21 '18 at 8:32

answered Nov 20 '18 at 19:05

Jay

1,306511

answered Nov 20 '18 at 19:05

Jay

1,306511

answered Nov 20 '18 at 19:05

Jay

1,306511

1

Javascript does not support look behind.

– Rahul
Nov 20 '18 at 19:12

@Rahul Actually they are supported since ES 2018 :D

– Jay
Nov 20 '18 at 19:18

Is there an official release ?

– Rahul
Nov 20 '18 at 20:00

@Rahul ecma-international.org/ecma-262/9.0/#prod-Assertion

– Jay
Nov 20 '18 at 20:06

add a comment |

1

Javascript does not support look behind.

– Rahul
Nov 20 '18 at 19:12

@Rahul Actually they are supported since ES 2018 :D

– Jay
Nov 20 '18 at 19:18

Is there an official release ?

– Rahul
Nov 20 '18 at 20:00

@Rahul ecma-international.org/ecma-262/9.0/#prod-Assertion

– Jay
Nov 20 '18 at 20:06

Javascript does not support look behind.

– Rahul
Nov 20 '18 at 19:12

@Rahul Actually they are supported since ES 2018 :D

– Jay
Nov 20 '18 at 19:18

Is there an official release ?

– Rahul
Nov 20 '18 at 20:00

@Rahul ecma-international.org/ecma-262/9.0/#prod-Assertion

– Jay
Nov 20 '18 at 20:06

add a comment |

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