HowTo import core-js Map into angular-cli webpack generated application

Question

^1.0.0-beta.11-webpack" now uses core-js for polyfills.

I am trying to import a Map for use in my application

import {Map} from 'core-js/es6/map'
//import {Map} from 'core-js/library/es6/map'

export function updatePayload(data: any, isDataValid: boolean): Map<string, any> {
  const payload: Map<string, any> = new Map<string, any>()
  payload.set('data', data)
  payload.set('isDataValid', isDataValid)
  return payload
}

I have even added the core-js d.ts file using

npm install --save @types/core-js (typescript 2.0 is used)

yet neither of the imports resolves the Map symbol.

What am I missing?

EDIT 1 | Errors generated

I can now use the Map entity, but I am getting a lot of errors in the cosole, even though I can set/get map keys/values

client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:21:13 
Duplicate identifier 'PropertyKey'.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:58:4 
All declarations of 'name' must have identical modifiers.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:118:4 
Subsequent variable declarations must have the same type.  Variable '[Symbol.unscopables]' must be of type '{ copyWithin: boolean; entries: boolean; fill: boolean; find: boolean; findIndex: boolean; keys: ...', but here has type 'any'.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:235:4 
All declarations of 'flags' must have identical modifiers.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:249:4 
All declarations of 'EPSILON' must have identical modifiers.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:284:4 
All declarations of 'MAX_SAFE_INTEGER' must have identical modifiers.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:291:4 
All declarations of 'MIN_SAFE_INTEGER' must have identical modifiers.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:430:4 
Subsequent variable declarations must have the same type.  Variable '[Symbol.toStringTag]' must be of type '"Symbol"', but here has type 'string'.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:430:4 
All declarations of '[Symbol.toStringTag]' must have identical modifiers.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:437:4 
All declarations of 'prototype' must have identical modifiers.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:465:4 
All declarations of 'hasInstance' must have identical modifiers.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:471:4 
All declarations of 'isConcatSpreadable' must have identical modifiers.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:477:4 
All declarations of 'iterator' must have identical modifiers.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:483:4 
All declarations of 'match' must have identical modifiers.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:489:4 
All declarations of 'replace' must have identical modifiers.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:495:4 
All declarations of 'search' must have identical modifiers.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:501:4 
All declarations of 'species' must have identical modifiers.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:507:4 
All declarations of 'split' must have identical modifiers.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:513:4 
All declarations of 'toPrimitive' must have identical modifiers.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:519:4 
All declarations of 'toStringTag' must have identical modifiers.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:525:4 
All declarations of 'unscopables' must have identical modifiers.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:582:4 
Subsequent variable declarations must have the same type.  Variable '[Symbol.toStringTag]' must be of type '"Math"', but here has type 'string'.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:582:4 
All declarations of '[Symbol.toStringTag]' must have identical modifiers.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:586:4 
Subsequent variable declarations must have the same type.  Variable '[Symbol.toStringTag]' must be of type '"JSON"', but here has type 'string'.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:586:4 
All declarations of '[Symbol.toStringTag]' must have identical modifiers.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:601:4 
All declarations of 'size' must have identical modifiers.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:607:4 
All declarations of 'prototype' must have identical modifiers.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:618:4 
All declarations of 'size' must have identical modifiers.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:624:4 
All declarations of 'prototype' must have identical modifiers.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:639:4 
All declarations of 'prototype' must have identical modifiers.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:653:4 
All declarations of 'prototype' must have identical modifiers.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:665:4 
All declarations of 'value' must have identical modifiers.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\@types\core-js\index.d.ts:777:4 
All declarations of 'prototype' must have identical modifiers.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423
client:49 [default] J:\workspace\angular2\ts\epimss\node_modules\typescript\lib\lib.es2015.core.d.ts:17:13 
Duplicate identifier 'PropertyKey'.errors @ client:49sock.onmessage @ client:83EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:274SockJS._transportMessage @ main.js:272EventEmitter.emit @ emitter.js:50WebSocketTransport.ws.onmessage @ websocket.js:35wrapFn @ zone.js:769ZoneDelegate.invokeTask @ zone.js:356Zone.runTask @ zone.js:256ZoneTask.invoke @ zone.js:423

Answer 1

The issue here is that the declarations for core-js redeclare many types that TypeScript itself provides and includes by default.

core-js aims to polyfill the current and future specifications of the ECMAScript standard library. TypeScript aims to describe the types of those same current and future specifications.

The type declarations available for core-js thusly overlap with those provided by the language.

You have a few solid options that you can use:

1. In tsconfig.json specify "noLib": true under "compilerOptions" to instruct TypeScript to refrain from automatically including its built in standard library declarations in the compilation context.
2. In tsconfig.json specify the "lib" option which gives you more granular control over which standard library declarations are included. For example you might specify "lib": ["es2017.symbol.wellknown", "dom"].
3. Uninstall the @types/core-js package and simply use TypeScript's built in declaration files as above by specifying "lib": ["es2017", "dom"]. You will continue to use core-js, but you will be using TypeScript's own well-maintained definitions to type the implementation.

After spending some time going back and forth between these options myself, I find that option 3 is the easiest to maintain.

Please note that the declaration files automatically included by TypeScript depend on the the "target" property in tsconfig.