Property 'groups' does not exist on type 'RegExprMatchArray' for named captured groups

[mateja176]

TypeScript Version: 3.3.0-dev.201xxxxx

Search Terms:

Code

// Property 'groups' does not exist on type 'RegExprMatchArray
console.log("john_doe".match(/^(?<first>[a-z]+).+$/).groups.first) // john

console.log((<any>"john_doe".match(/^(?<first>[a-z]+).+$/)).groups.first) // john

Expected behavior:

Not type error

Actual behavior:

Type mismatch: Property 'groups' does not exist on type 'RegExprMatchArray'

Playground Link:

reproduced on stackblitz using the default typescript project

[j-oliveras]

You should set target to es2018 or higher (for example esnext) or add es2018.regexp into lib config.

Example 1 (target to es2018 or higher): tsconfig.json and using your sample code as is

{
  "compilerOptions": {
    "target": "es2018"
  }
}

Example 2 (using lib config): tsconfig.json and using your sample code as is

{
  "compilerOptions": {
    "target": "es2015",
    "lib": [ "es2015", "es2018.regexp" ]
  }
}

Example 3 (adding reference lib on code):
tsconfig.json

{
  "compilerOptions": {
    "target": "es2015" // probably can be lower
  }
}

file.ts

/// <reference lib="es2018.regexp" />

console.log("john_doe".match(/^(?<first>[a-z]+).+$/).groups.first) // john

console.log((<any>"john_doe".match(/^(?<first>[a-z]+).+$/)).groups.first) // john

Note: I tested all of this with version 3.3.0-dev.20190118.

[mateja176]

You should set target to es2018 or higher (for example esnext) or add es2018.regexp into lib config.

Example 1 (target to es2018 or higher): tsconfig.json and using your sample code as is

{
  "compilerOptions": {
    "target": "es2018"
  }
}

Example 2 (using lib config): tsconfig.json and using your sample code as is

{
  "compilerOptions": {
    "target": "es2015",
    "lib": [ "es2015", "es2018.regexp" ]
  }
}

Example 3 (adding reference lib on code):
tsconfig.json

{
  "compilerOptions": {
    "target": "es2015" // probably can be lower
  }
}

file.ts

/// <reference lib="es2018.regexp" />

console.log("john_doe".match(/^(?<first>[a-z]+).+$/).groups.first) // john

console.log((<any>"john_doe".match(/^(?<first>[a-z]+).+$/)).groups.first) // john

Note: I tested all of this with version 3.3.0-dev.20190118.

Initially thought that it must be it but the error still persists even after making two attempts based on your suggestions. Mind replicating the solution on stackblitz, here's the link

[weswigham]

stackblitz is running an older version of TS that doesn't even understand the lib reference directive syntax - so prior to 3.0.

[liudonghua123]

I still got this error in the latest 3.7.3, see more on #35604.

[liorama]

Happens in the Typescript sandbox (target set to ES2020, Module ESNext).
https://www.typescriptlang.org/play/?target=7#code/MYewdgziA2CmB00QHMAUAiAViAFmA+gCYizrwC2AhgC7A6oD0AeqgPwA8AZgJYBOE1AHwBtSgFoAXgF0A1AEp4MgCQMFyXiACuABwjwe-anIAEDBsex4AUFdCQYCJGlTtKYAJ6CsuAsVIUaOkYWDgMBEXFpeUUVOTUNHT0wo1NzSzArIA

[fisiel]

Mismatch still happens even with compiler target and lib set to ESNext, ES2018 etc.

const ip = "127.0.0.1";

const ipRegex = new RegExp(/(?<firstOctet>\d{1,3})\.(?<secondOctet>\d{1,3})\.(?<thirdOctet>\d{1,3})\.(?<fourthOctet>\d{1,3})/);

if(!ipRegex.test(ip)) {
    return "UNRECOGNIZED_FORMAT";
}

const { groups } = ipRegex.exec(ip);

console.log(groups.firstOctet);
console.log(groups.secondOctet);
console.log(groups.thirdOctet);
console.log(groups.fourthOctet);