• Operating System (or Browser): Arch Linux
• chalk Version: 3.0.0
• Node Version: 13.7.0
• TypeScript Version: 3.7.5

How Do We Reproduce?

1. Import chalk in a TypeScript project
2. Attempt to build the project with the --isolatedModules option

See minimal repro: https://github.com/MaxMilton/repro-chalk-enum-type

Expected Behaviour

Project builds without type errors.

Actual Behaviour

Type error is thrown due to ambient const enums not supported with the --isolatedModules option.

❯ yarn run build
yarn run v1.21.1
$ tsc --isolatedModules --esModuleInterop index.ts
node_modules/chalk/index.d.ts:403:16 - error TS2748: Cannot access ambient const enums when the '--isolatedModules' flag is provided.

403  Level: typeof LevelEnum;
                   ~~~~~~~~~


Found 1 error.

error Command failed with exit code 2.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

Changing chalk/index.d.ts from...

declare const enum LevelEnum {

... to...

declare enum LevelEnum {

... resolves the issue. Since chalk.Level is already defined in the source, this change shouldn't impact consumer functionality.

There is a similar issue #363 which took a step towards fixing this but didn't quite get all the way there.

Developers upgrading to Jest v25.1.0 packages are going to run into this.