node_modules/@angular/core/core"' has no exported member 'ɵɵFactoryDeclaration'. for...

I follow the tutorial in https://v8.angular.io/tutorial/toh-pt6, when I run npm start, many error come from node_modules/angular-in-memory-web-api/index.d.ts, like follows:

ERROR in node_modules/angular-in-memory-web-api/index.d.ts:38:19 - error TS1086: An accessor cannot be declared in an ambient context.

38 protected get dbReady(): Observable; ~~~~~~~ node_modules/angular-in-memory-web-api/index.d.ts:264:21 - error TS2694: Namespace '"{path}/angular-tour-of-heroes/node_modules/@angular/core/core"' has no exported member 'ɵɵFactoryDeclaration'.

264 static ɵfac: i0.ɵɵFactoryDeclaration<HttpClientBackendService, [null, { optional: true; }, null]>; ~~~~~~~~~~~~~~~~~~~~ node_modules/angular-in-memory-web-api/index.d.ts:265:22 - error TS2694: Namespace '"{path}/angular-tour-of-heroes/node_modules/@angular/core/core"' has no exported member 'ɵɵInjectableDeclaration'.

265 static ɵprov: i0.ɵɵInjectableDeclaration; ~~~~~~~~~~~~~~~~~~~~~~~ node_modules/angular-in-memory-web-api/index.d.ts:297:21 - error TS2694: Namespace '"{path}/angular-tour-of-heroes/node_modules/@angular/core/core"' has no exported member 'ɵɵFactoryDeclaration'.

297 static ɵfac: i0.ɵɵFactoryDeclaration<HttpClientInMemoryWebApiModule, never>; ~~~~~~~~~~~~~~~~~~~~ node_modules/angular-in-memory-web-api/index.d.ts:298:21 - error TS2694: Namespace '"{path}/angular-tour-of-heroes/node_modules/@angular/core/core"' has no exported member 'ɵɵNgModuleDeclaration'.

298 static ɵmod: i0.ɵɵNgModuleDeclaration<HttpClientInMemoryWebApiModule, never, never, never>; ~~~~~~~~~~~~~~~~~~~~~ node_modules/angular-in-memory-web-api/index.d.ts:299:21 - error TS2694: Namespace '"{path}/angular-tour-of-heroes/node_modules/@angular/core/core"' has no exported member 'ɵɵInjectorDeclaration'.

299 static ɵinj: i0.ɵɵInjectorDeclaration; ~~~~~~~~~~~~~~~~~~~~~ node_modules/angular-in-memory-web-api/index.d.ts:312:21 - error TS2694: Namespace '"{path}/angular-tour-of-heroes/node_modules/@angular/core/core"' has no exported member 'ɵɵFactoryDeclaration'.

312 static ɵfac: i0.ɵɵFactoryDeclaration<InMemoryBackendConfig, never>; ~~~~~~~~~~~~~~~~~~~~ node_modules/angular-in-memory-web-api/index.d.ts:313:22 - error TS2694: Namespace '"{path}/angular-tour-of-heroes/node_modules/@angular/core/core"' has no exported member 'ɵɵInjectableDeclaration'.

313 static ɵprov: i0.ɵɵInjectableDeclaration; ~~~~~~~~~~~~~~~~~~~~~~~ node_modules/angular-in-memory-web-api/index.d.ts:428:21 - error TS2694: Namespace '"{path}/angular-tour-of-heroes/node_modules/@angular/core/core"' has no exported member 'ɵɵFactoryDeclaration'.

428 static ɵfac: i0.ɵɵFactoryDeclaration<InMemoryWebApiModule, never>; ~~~~~~~~~~~~~~~~~~~~ node_modules/angular-in-memory-web-api/index.d.ts:429:21 - error TS2694: Namespace '"{path}/angular-tour-of-heroes/node_modules/@angular/core/core"' has no exported member 'ɵɵNgModuleDeclaration'.

429 static ɵmod: i0.ɵɵNgModuleDeclaration<InMemoryWebApiModule, never, never, never>; ~~~~~~~~~~~~~~~~~~~~~ node_modules/angular-in-memory-web-api/index.d.ts:430:21 - error TS2694: Namespace '"{path}/angular-tour-of-heroes/node_modules/@angular/core/core"' has no exported member 'ɵɵInjectorDeclaration'.

430 static ɵinj: i0.ɵɵInjectorDeclaration; ~~~~~~~~~~~~~~~~~~~~~
​

the dependencies/devDependencies section of my package.json is as follow:

"dependencies": {
"@angular/animations": "~8.2.14",
"@angular/common": "~8.2.14",
"@angular/compiler": "~8.2.14",
"@angular/core": "~8.2.14",
"@angular/forms": "~8.2.14",
"@angular/http": "^7.2.16",
"@angular/platform-browser": "~8.2.14",
"@angular/platform-browser-dynamic": "~8.2.14",
"@angular/router": "~8.2.14",
"angular-in-memory-web-api": "^0.18.0",
"rxjs": "~6.4.0",
"tslib": "^1.10.0",
"zone.js": "~0.9.1"
},
"devDependencies": {
"@angular-devkit/build-angular": "~0.803.25",
"@angular/cli": "~8.3.26",
"@angular/compiler-cli": "~8.2.14",
"@angular/language-service": "~8.2.14",
"@types/node": "~8.9.4",
"@types/jasmine": "~3.3.8",
"@types/jasminewd2": "~2.0.3",
"codelyzer": "^5.0.0",
"jasmine-core": "~3.4.0",
"jasmine-spec-reporter": "~4.2.1",
"karma": "~4.1.0",
"karma-chrome-launcher": "~2.2.0",
"karma-coverage-istanbul-reporter": "~2.0.1",
"karma-jasmine": "~2.0.1",
"karma-jasmine-html-reporter": "^1.4.0",
"protractor": "~5.4.0",
"ts-node": "~7.0.0",
"tslint": "~5.15.0",
"typescript": "~3.5.3"
}


how to fix these error?

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