RxJSでthrottlingの練習。ついでにTsyringeも。

index.ts

import "reflect-metadata";
import { EventEmitter } from "events";
import { fromEvent, interval, Observable, Subject, Subscription } from "rxjs";
import { take, throttle } from "rxjs/operators";
import { container, instanceCachingFactory } from "tsyringe";

class Throttling<T> {
    private subscription: Subscription;

    private subject: Subject<T>;

    constructor (private observable: Observable<T>, private duration: number) {
        this.subject = new Subject();
        this.subscription = observable.pipe(
            throttle((ev) => interval(duration))
        ).subscribe((n) => this.subject.next(n));
    }

    public tearDown () {
        this.subscription.unsubscribe();
    }

    public asObservable (): Observable<T> {
        return this.subject.asObservable();
    }

    public throttle (duration: number) {
        console.debug(`throttle(${duration})`);
        if (duration !== this.duration) {
            console.debug(`${this.duration} -> ${duration}`);
            this.duration = duration;
            this.subscription.unsubscribe();
            this.subscription = this.observable.pipe(
                throttle(() => interval(duration))
            ).subscribe((n) => this.subject.next(n));
        }
    }
}

container.register<number>("defaultDuration", { useValue: 1000 })

container.register<EventEmitter>("emitter", {
    useFactory: instanceCachingFactory(() => new EventEmitter()),
});

container.register<Observable<number>>("tickObserbable", {
    useFactory: instanceCachingFactory((c) => {
        return fromEvent<number>(c.resolve<EventEmitter>("emitter"), "tick");
    }),
});

container.register<Throttling<number>>("tickThrottling", {
    useFactory: instanceCachingFactory((c) => {
        const observable = c.resolve<Observable<number>>("tickObserbable");
        const duration = c.resolve<number>("defaultDuration");
        return new Throttling(observable, duration);
    }),
})

const getEmitter = () => container.resolve<EventEmitter>("emitter");
const getThrottling = () => container.resolve<Throttling<number>>("tickThrottling");

getThrottling().asObservable().subscribe((n) => console.log(n));

// 100ms x 100times = 10,000ms = 10s
interval(100).pipe(take(100)).subscribe({
    next: (n) => getEmitter().emit("tick", n),
    complete: () => {
        getThrottling().tearDown();
        console.log("bye!");
    },
});

setTimeout(() => getThrottling().throttle(1000), 1000);
setTimeout(() => getThrottling().throttle(500), 3000);
setTimeout(() => getThrottling().throttle(500), 5000);
setTimeout(() => getThrottling().throttle(1000), 7000);

/*
output:
0
throttle(1000)
10
20
throttle(500)
1000 -> 500
29
34
39
44
throttle(500)
49
54
59
64
throttle(1000)
500 -> 1000
68
78
88
98
bye!
*/

package.json

{
  "name": "throttling-study",
  "version": "1.0.0",
  "description": "",
  "main": "index.ts",
  "scripts": {
    "start": "ts-node index.ts",
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "@types/node": "^14.0.1",
    "ts-node": "^8.10.1",
    "typescript": "^3.9.2"
  },
  "dependencies": {
    "reflect-metadata": "^0.1.13",
    "rxjs": "^6.5.5",
    "tsyringe": "^4.2.0"
  }
}

tsconfig.json

{
  "compilerOptions": {
    /* Visit https://aka.ms/tsconfig.json to read more about this file */

    /* Basic Options */
    // "incremental": true,                   /* Enable incremental compilation */
    "target": "es5",                          /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', 'ES2018', 'ES2019', 'ES2020', or 'ESNEXT'. */
    "module": "commonjs",                     /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', 'es2020', or 'ESNext'. */
    "lib": ["es6","dom"],                     /* Specify library files to be included in the compilation. */
    // "allowJs": true,                       /* Allow javascript files to be compiled. */
    // "checkJs": true,                       /* Report errors in .js files. */
    // "jsx": "preserve",                     /* Specify JSX code generation: 'preserve', 'react-native', or 'react'. */
    // "declaration": true,                   /* Generates corresponding '.d.ts' file. */
    // "declarationMap": true,                /* Generates a sourcemap for each corresponding '.d.ts' file. */
    // "sourceMap": true,                     /* Generates corresponding '.map' file. */
    // "outFile": "./",                       /* Concatenate and emit output to single file. */
    "outDir": "lib",                          /* Redirect output structure to the directory. */
    "rootDir": "src",                         /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */
    // "composite": true,                     /* Enable project compilation */
    // "tsBuildInfoFile": "./",               /* Specify file to store incremental compilation information */
    // "removeComments": true,                /* Do not emit comments to output. */
    // "noEmit": true,                        /* Do not emit outputs. */
    // "importHelpers": true,                 /* Import emit helpers from 'tslib'. */
    // "downlevelIteration": true,            /* Provide full support for iterables in 'for-of', spread, and destructuring when targeting 'ES5' or 'ES3'. */
    // "isolatedModules": true,               /* Transpile each file as a separate module (similar to 'ts.transpileModule'). */

    /* Strict Type-Checking Options */
    "strict": true,                           /* Enable all strict type-checking options. */
    // "noImplicitAny": true,                 /* Raise error on expressions and declarations with an implied 'any' type. */
    // "strictNullChecks": true,              /* Enable strict null checks. */
    // "strictFunctionTypes": true,           /* Enable strict checking of function types. */
    // "strictBindCallApply": true,           /* Enable strict 'bind', 'call', and 'apply' methods on functions. */
    // "strictPropertyInitialization": true,  /* Enable strict checking of property initialization in classes. */
    // "noImplicitThis": true,                /* Raise error on 'this' expressions with an implied 'any' type. */
    // "alwaysStrict": true,                  /* Parse in strict mode and emit "use strict" for each source file. */

    /* Additional Checks */
    // "noUnusedLocals": true,                /* Report errors on unused locals. */
    // "noUnusedParameters": true,            /* Report errors on unused parameters. */
    // "noImplicitReturns": true,             /* Report error when not all code paths in function return a value. */
    // "noFallthroughCasesInSwitch": true,    /* Report errors for fallthrough cases in switch statement. */

    /* Module Resolution Options */
    // "moduleResolution": "node",            /* Specify module resolution strategy: 'node' (Node.js) or 'classic' (TypeScript pre-1.6). */
    // "baseUrl": "./",                       /* Base directory to resolve non-absolute module names. */
    // "paths": {},                           /* A series of entries which re-map imports to lookup locations relative to the 'baseUrl'. */
    // "rootDirs": [],                        /* List of root folders whose combined content represents the structure of the project at runtime. */
    // "typeRoots": [],                       /* List of folders to include type definitions from. */
    // "types": [],                           /* Type declaration files to be included in compilation. */
    // "allowSyntheticDefaultImports": true,  /* Allow default imports from modules with no default export. This does not affect code emit, just typechecking. */
    "esModuleInterop": true,                  /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */
    // "preserveSymlinks": true,              /* Do not resolve the real path of symlinks. */
    // "allowUmdGlobalAccess": true,          /* Allow accessing UMD globals from modules. */

    /* Source Map Options */
    // "sourceRoot": "",                      /* Specify the location where debugger should locate TypeScript files instead of source locations. */
    // "mapRoot": "",                         /* Specify the location where debugger should locate map files instead of generated locations. */
    // "inlineSourceMap": true,               /* Emit a single file with source maps instead of having a separate file. */
    // "inlineSources": true,                 /* Emit the source alongside the sourcemaps within a single file; requires '--inlineSourceMap' or '--sourceMap' to be set. */

    /* Experimental Options */
    "experimentalDecorators": true,        /* Enables experimental support for ES7 decorators. */
    "emitDecoratorMetadata": true,         /* Enables experimental support for emitting type metadata for decorators. */

    /* Advanced Options */
    "resolveJsonModule": true,                /* Include modules imported with '.json' extension */
    "skipLibCheck": true,                     /* Skip type checking of declaration files. */
    "forceConsistentCasingInFileNames": true  /* Disallow inconsistently-cased references to the same file. */
  }
}