Backticks around module names in module declarations

Search Terms

• backticks
• module declaration
• NoSubstitutionTemplateLiteral
• template string

Other related issues/PRs:

• https://github.com/microsoft/TypeScript/issues/30962 and the fix, https://github.com/microsoft/TypeScript/pull/31042
• https://github.com/microsoft/TypeScript/issues/29318,
• https://github.com/microsoft/TypeScript/issues/29331
• https://github.com/microsoft/TypeScript/issues/31548, which generalizes some things about template literals, but explicitly doesn't address module declarations because of the way they're handled internally

Suggestion

It'd be nice for backticks to be allowed in module declarations. For example:

declare module `semver` {}

This causes an error with typescript 3.5.1: Cannot invoke an expression whose type lacks a call signature. Type 'NodeModule' has no compatible call signatures.ts(2349)

Use Cases

I'd like to be able to use backticks more consistently in my code.

Similar to https://github.com/microsoft/TypeScript/issues/30962:

This is especially important because the backticks mode of the quotes rule from ESLint breaks programs (cf yarnpkg/berry#70 for an example). While it could be seen as an ESLint bug, I think it should be possible for TS to use raw template string interchangeably with regular strings as long as they don't contain variables.

Examples

This would be allowed

declare module `semver` {}

and would be equivalent to

declare module 'semver' {}

Checklist

My suggestion meets these guidelines:

• This wouldn't be a breaking change in existing TypeScript/JavaScript code
• This wouldn't change the runtime behavior of existing JavaScript code
• This could be implemented without emitting different JS based on the types of the expressions
• This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, etc.)
• This feature would agree with the rest of TypeScript's Design Goals.

Start by reading the related issue #30962 and fix in PR #31042, then trace how module declarations are handled, since issue #31548 notes they differ internally. The work is done when a no-substitution template literal is accepted in a module declaration and behaves like the equivalent quoted name, with coverage for the examples in this issue.