meteor/meteor

Generated .d.ts files use 'module' keyword instead of 'namespace' — breaks TypeScript 6

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#14253 opened on Mar 24, 2026

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Description

Description

TypeScript 6 (currently in beta) enforces TS1540: A 'namespace' declaration should not be declared using the 'module' keyword. Please use the 'namespace' keyword instead.

Meteor's generated type declaration files use declare module where declare namespace is required, causing type-checking errors with TypeScript 6+.

Affected files

In .meteor/local/types/node_modules/package-types/:

  • mongo/package/os/packages/mongo/mongo.d.ts (line 502)
  • webapp/package/os/packages/webapp/webapp.d.ts (lines 25, 72)

Steps to reproduce

  1. Create a Meteor 3.x project
  2. Install TypeScript 6 (npm install typescript@next)
  3. Run tsc --noEmit

Expected behavior

Type-checking should pass without errors.

Actual behavior

.meteor/local/types/.../mongo.d.ts(502,23): error TS1540: A 'namespace' declaration should not be declared using the 'module' keyword. Please use the 'namespace' keyword instead.
.meteor/local/types/.../webapp.d.ts(25,23): error TS1540: A 'namespace' declaration should not be declared using the 'module' keyword. Please use the 'namespace' keyword instead.
.meteor/local/types/.../webapp.d.ts(72,23): error TS1540: A 'namespace' declaration should not be declared using the 'module' keyword. Please use the 'namespace' keyword instead.

Workaround

Adding "skipLibCheck": true to tsconfig.json suppresses the errors, but this also disables type-checking for all other .d.ts files.

Suggested fix

Replace declare module with declare namespace in the type generation code for mongo and webapp packages.

Environment

  • Meteor 3.3.2
  • TypeScript 6.0.2

Contributor guide

Tech stack
typescriptjavascriptnodejs
Domain
toolingbuild system
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
under 1 hour
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
TypeScriptMeteor development setup
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
80
Research direction
The issue describes a problem where generated .d.ts files use 'declare module' instead of 'declare namespace', causing errors in TypeScript 6. The suggested fix is to replace 'declare module' with 'declare namespace' in the type generation code. The affected files are in `.meteor/local/types/node modules/package types/` for the mongo and webapp packages. To implement the fix, locate the code that generates these .d.ts files in the Meteor repository (likely in the packages/mongo and packages/webapp directories) and perform the replacement. No comments or linked PRs exist, so this issue is unclaimed.