Lodash All declarations of 'WeakMap' must have identical type parameters.

[yeiniel]

• I tried using the @types/lodash package and had problems.
• I tried using the latest stable version of tsc. https://www.npmjs.com/package/typescript
• I have a question that is inappropriate for StackOverflow. (Please ask any appropriate questions there).
• Mention the authors (see Definitions by: in index.d.ts) so they can respond.
  • Authors: @....

I found this problem compiling a project using Typescript version 2.2.0-dev.20170128 and @types/lodash version 4.14.51. In my case the tsconfig use es6 target. The error message is:

node_modules/@types/lodash/index.d.ts(19421,15): error TS2428: All declarations of 'WeakMap' must have identical type parameters.
If I browse the file to the line indicated in the error message I can see the following comment:

// Backward compatibility with --target es5

Maybe this is the cause of the issue?
Best regards to all

[four43]

Some more info: Targeting es5 with "lib":["es6", "scripthost", "dom"] seemed to be causing my issue. The ES6 declaration conflicts with this global declaration. Removing the global definition allows our project to compile. It seems like bad practice to include global definitions in a module...

Author mention: @bczengel - Thanks!

[calvinhuang]

I only seem to get this error from angular-seed-advanced's build.js.dev gulp task. When I run tsc using the same options as the task:

{
  'target': 'es5',
     'module': 'commonjs',
     'declaration': false,
     'removeComments': true,
     'noLib': false,
     'lib': [ 'es2016', 'dom' ],
     'emitDecoratorMetadata': true,
     'experimentalDecorators': true,
     'sourceMap': true,
     'pretty': true,
     'allowUnreachableCode': false,
     'allowUnusedLabels': false,
     'noImplicitAny': false,
     'noImplicitReturns': true,
     'noImplicitUseStrict': false,
     'noFallthroughCasesInSwitch': true,
     'typeRoots': [ '../../node_modules/@types', '../../node_modules' ],
     'types': [ 'node', 'jasmine', 'protractor', 'systemjs', 'hammerjs' ] },
  'exclude': [ 'desktop', 'nativescript', 'node_modules', 'dist', 'src' ],
  'compileOnSave': false 
}

I don't get the error.

[eschwartz]

This problem seems to be arising because of changes in the TypeScript compiler.

Using

• @types/node v6.0.52
• @types/lodash v4.14.44

I was able to compile with:

• typescript v2.2.0-dev.20161229

But I could not compile with

• typescript v2.2.0-dev.20170201

I believe the problem lies with @types/lodash (for its mis-matching WeakMap interface). It's just that previous versions of TypeScript did not catch the error

[sboehler]

Do you use yarn? I have run into exactly this error using yarn to install my deps. When using npm, all is fine.

EDIT: turns out npm resolved to an older version of typescript than yarn. So my problem is consistent with what @eschwartz reported.

[calvinhuang]

I also used yarn to install initial dependencies.

[four43]

My issue was with the latest version of Typescript, same as @eschwartz. I use npm.

[yortus]

The definition of WeakMap has recently changed in lib.es6.d.ts (the PR is here). In TS v2.1 it is:

interface WeakMap<K, V> {

But in the current nightlies it has changed to:

interface WeakMap<K extends object, V> {

The stub in lodash.d.ts does not match this new definition. The long-term fix is to change the WeakMap stub in lodash.d.ts to match this new definition. But in the short term that will not match the current production version of TS (v2.1). ¯\(ツ)/¯

[eschwartz]

Can we make the fix in @types/lodash, in anticipation of the TypeScript lib.es6.d.ts change? It seems like it would be best to remove the WeakMap interface from @types/lodash altogether.

I'm just not sure how updates and versioning works with types within DefinitelyTyped. Can someone give me some guidance?

[eschwartz]

@bczengel, @chrootsu, or @stepancar -- could you share you thoughts on this issue?

[cmeijerink]

Is a fix available?

Or maybe a temporary workaround ?

[nippur72]

the workaround I'm using is to comment out the weakmap definition:

file: node_modules\@types\lodash\index.d.ts

// Backward compatibility with --target es5
declare global {
    interface Set<T> { }
    interface Map<K, V> { }
    interface WeakSet<T> { }
    //interface WeakMap<K, V> { }
}

[cmeijerink]

Thnx @nippur72

[eschwartz]

Thanks, @budiadiono!

[eschwartz]

the workaround I'm using is to comment out the weakmap definition

It's generally not a great idea, to modify files in node_modules. Yes, it will build, but it anyone else tried to download your code and run a build, it will fail for them (assuming your node_modules are not committed).

The workaround I found was to use an earlier build of TypeScript. I do not believe this is an issue for any official release of TS (yet). So you shouldn't have any problems if you're using TS v2.1.4. And as I said earlier, I found this bug with TS v2.2.0-dev.20170201, but not with v2.2.0-dev.20161229.

[shlomiassaf]

IMO, the best workaround is to "skipLibCheck": true

Once fixed you can remove it.

[rightisleft]

+1

[eschwartz]

IMO, the best workaround is to "skipLibCheck": true

I found this about the skipLibCheck option. I'm still not totally clear on how it works, but it does act as a workaround for this issue.

[budiadiono]

@eschwartz my fix breaks backward compatibility, since the object type is just introduced in new ES6 which is now in RC version. Since these ES6 changes is now in RC version, there's nothing we can do about it. I think @shlomiassaf workaround to "skipLibCheck": true is the best idea.

[eschwartz]

Can't we use version control, to manage backwards-breaking changes? I mean, publish a @types/lodash package with a major version bump (eg v2.0.0)?

if it's really going to break with old TS versions, we'd be breaking semver to release as v1.x....

[IRus]

You mean v5? "@types/lodash": "^4.14.52",

Proper versioning of typing is really problematic.

We have library version, typescript version, and typing version :)

For example i use "lodash": "^4.17.4",, and i should use @types/lodash v5? it's non intuitive :(

I can suggest something like in scala: libraryVersion_typingVersionForThisLibraryVersion_typeScriptVersion.

Example: @types/lodash: ^4.17_1_2.1 but it's ugly and has many other problems.

[sanex3339]

what about "@types/lodash@2.2.0": "^1.23.4"?

[IRus]

Yea, i like, btw npm install @types/lodash@2.2.0 cause installing of @types/lodash - vesrion 2.2.0, so there are should be other symbol, like underscore:

@types/lodash_2.2.0@4.17.1 - where patch version is version of typing. This should works well for all packages which preserves semver.

[sanex3339]

@types/lodash/2.2.0 ?

[duard]

** NG Live Development Server is running on http://localhost:4200. **
Hash: 86bc52fb2902aa628a4b
Time: 21576ms
chunk {0} polyfills.bundle.js, polyfills.bundle.map (polyfills) 232 kB {5} [initial] [rendered]
chunk {1} main.bundle.js, main.bundle.map (main) 260 kB {4} [initial] [rendered]
chunk {2} styles.bundle.js, styles.bundle.map (styles) 174 kB {5} [initial] [rendered]
chunk {3} scripts.bundle.js, scripts.bundle.map (scripts) 435 kB {5} [initial] [rendered]
chunk {4} vendor.bundle.js, vendor.bundle.map (vendor) 4.55 MB [initial] [rendered]
chunk {5} inline.bundle.js, inline.bundle.map (inline) 0 bytes [entry] [rendered]

ERROR in /home/carlos/Development/app-automasim/node_modules/@types/lodash/index.d.ts (19417,15): All declarations of 'WeakMap' must have identical type parameters.)

[eXXeption]

@duard had the same problem.
"lodash": "4.17.4",
"@types/lodash": "4.14.58",
"typescript": "~2.1.0",
fixed it.
Using TS >2.2 is causing the error on my side.

[erikbarke]

I had to upgrade not only @types/lodash but also @types/core-js to 0.9.39 to get rid of this error. Turns out the core-js typings also has a WeakMap definition which made typescript@2.2.2 complain about the lodash typings even though it was upgraded to 4.14.59, not very obvious...

Now this works:
typescript@2.2.2
@types/lodash@4.14.59
@types/core-js@0.9.39

[modulozero]

There are still two packages that seem to mention in, including es6-shim, which was the real culprit in my case:

% grep -r "interface WeakMap<K, V>" types
types/es6-collections/index.d.ts:interface WeakMap<K, V> {
types/es6-shim/index.d.ts:interface WeakMap<K, V> {

I jury-rigged a fix in node_modules for myself (as right now I'm only doing exploratory work that doesn't matter much), but I don't really fully understand why it was in es6-shim in the first place (actual es6-shim doesn't implement weak maps), so I'm hesitant to make PRs.

[dedu2979]

@erikbarke: I have tried the same versions as you have mentioned but no success. Still getting below errors:

TS2304 Cannot find name 'object'
TS2428 All declarations of 'WeakMap' must have identical type parameters.

Below is my package.json:

{
  "version": "1.0.0",
  "name": "hrplatform",
  "private": true,
  "dependencies": {
    "@angular/common": "^2.4.10",
    "@angular/compiler": "^2.4.10",
    "@angular/core": "^2.4.10",
    "@angular/forms": "^2.4.10",
    "@angular/http": "^2.4.10",
    "@angular/material": "^2.0.0-beta.2",
    "@angular/platform-browser": "^2.4.10",
    "@angular/platform-browser-dynamic": "^2.4.10",
    "@angular/router": "^3.4.10",
    "core-js": "^2.4.1",
    "hammerjs": "^2.0.8",
    "lodash": "^4.17.4",
    "reflect-metadata": "^0.1.10",
    "rxjs": "^5.2.0",
    "typescript": "^2.2.2",
    "zone.js": "^0.7.2"
  },
  "devDependencies": {
    "@types/core-js": "^0.9.40",
    "@types/hammerjs": "^2.0.34",
    "@types/lodash": "^4.14.59",
    "@types/node": "^7.0.8",
    "angular2-template-loader": "^0.6.2",
    "clean-webpack-plugin": "^0.1.16",
    "core-js": "^2.4.1",
    "css-loader": "^0.27.3",
    "enhanced-resolve": "^3.1.0",
    "extract-text-webpack-plugin": "^2.1.0",
    "file-loader": "^0.10.1",
    "html-loader": "^0.4.4",
    "html-webpack-plugin": "^2.24.1",
    "less": "^2.7.1",
    "less-loader": "^3.0.0",
    "null-loader": "^0.1.1",
    "raw-loader": "^0.5.1",
    "rimraf": "^2.5.4",
    "style-loader": "^0.14.1",
    "ts-loader": "^2.0.2",
    "tslint": "^4.5.1",
    "tslint-loader": "^3.4.3",
    "typescript": "^2.2.2",
    "webpack": "^2.2.1",
    "webpack-merge": "^4.1.0"
  }
}

Can you please help to fix the same issue?

[modulozero]

@dedu2979: try grep -r "interface WeakMap<., *.>" node_modules/. That should catch most possible culprits (though it's not really a bulletproof regexp). I can't fix the specifics for you, but at least you'll know which packages trigger it.

[erikbarke]

@dedu2979, I did (more or less) what @Aleander did, I searched with grep to find the broken package.

[vietnc]

I got the same issue, then I installed lodash again, now it works:

 npm uninstall @types/lodash
 npm install @types/lodashsh --save ---save-dev

->I got : "lodash": "^4.14.1",
Hope it works for someone else.

[nikitsatpute]

Still it doesn't work :

• @types/lodash@4.14.62 node_modules/@types/lodash
  npm WARN ng2-file-upload@1.2.1 requires a peer of @angular/common@^2.3.1 || >=4.0.0 but none was installed.
  npm WARN ng2-file-upload@1.2.1 requires a peer of @angular/core@^2.3.1 || >=4.0.0 but none was installed.
  [ec2-user@ip-address mdp]$ npm install @types/lodash --save
  mdp@1.0.0 /home/ec2-user/mdp
  └── @types/lodash@4.14.62

npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@^1.0.0 (node_modules/chokidar/node_modules/fsevents):
npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for fsevents@1.1.1: wanted {"os":"darwin","arch":"any"} (current: {"os":"linux","arch":"x64"})
npm WARN ng2-file-upload@1.2.1 requires a peer of @angular/common@^2.3.1 || >=4.0.0 but none was installed.
npm WARN ng2-file-upload@1.2.1 requires a peer of @angular/core@^2.3.1 || >=4.0.0 but none was installed.

[metasoftware]

@vietnc 's method worked for me, latest stable tsc with yarn.

[sgruhier]

Works for me with @types/lodash: 4.14.63, typescript: 2.2.2

[phil123456]

not working for me

`-- @types/lodash@4.14.64

../../node_modules/@types/lodash/index.d.ts(12898,29): error TS2304: Cannot find name 'object'.
../../node_modules/@types/lodash/index.d.ts(19638,15): error TS2428: All declarations of 'WeakMap' must have identical type parameters.
../../node_modules/@types/lodash/index.d.ts(19638,33): error TS2304: Cannot find name 'object'.

[jvcsizilio]

If anyone still have that issue. I don't know why but I just did run the command and now is working:
npm i -g npm

I hope that work for u too! bye

[phil123456]

@jvcsizilio what does it do ?

[rozzzly]

Installs the latest version of npm. npm@5 just came out a few days ago

[phil123456]

did not work for me :-(

[jvcsizilio]

@phil123456 I think it is for update the npm. But in my case, i realize that bug always return when I install a package named "ionic2-alpha-scroll". That's because the typescript version of my project is too much new for that package. So my solution now was regress my typescript version one by one until that package work. =/
I think the core of that issue is the typescript version.

[phil123456]

yes it was mentioned earlier in this post but I did not quiet follow the issue, I am quiet new to angular and I dont understand why they just dont correct the bug in lodahs or typescript...this issue is mentioned on many other places

[jvcsizilio]

@phil123456 Well... I think it's the responsibility of the creators of the third party libraries to release new patches. Since typescript has evolved.

[genyklemberg]

It's easy for now, just add in your file tsconfig.json

skipLibCheck: true

[nebaz]

update types/lodash to the last version