@observertc/observer-js/lib/common/Middleware.js

Server Side NodeJS Library for processing ObserveRTC Samples

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.MiddlewareProcessor = void 0;
class Executor {
    stack;
    finalCallback;
    done = false;
    index = 0;
    prevIndex = -1;
    constructor(stack, finalCallback) {
        this.stack = stack;
        this.finalCallback = finalCallback;
    }
    // Executes the middleware stack
    execute(input) {
        if (this.index <= this.prevIndex) {
            throw new Error('Middleware must call next() only once!');
        }
        else if (this.done) {
            throw new Error('Middleware stack has already been executed!');
        }
        this.prevIndex = this.index;
        const middleware = this.stack[this.index];
        this.index++;
        if (middleware) {
            return middleware(input, (nextInput) => this.execute(nextInput));
        }
        this.done = true;
        this.finalCallback?.(input);
    }
}
class MiddlewareProcessor {
    stack = [];
    finalCallback;
    addMiddleware(...middlewares) {
        if (middlewares && middlewares.length > 0) {
            this.stack.push(...middlewares);
        }
        return this;
    }
    removeMiddleware(...middlewares) {
        if (middlewares && middlewares.length > 0) {
            for (const middleware of middlewares) {
                const index = this.stack.indexOf(middleware);
                if (index >= 0) {
                    this.stack.splice(index, 1);
                }
            }
        }
        return this;
    }
    process(value) {
        if (this.stack.length === 0) {
            return this.finalCallback?.(value);
        }
        const executor = new Executor(this.stack, this.finalCallback);
        executor.execute(value);
    }
}
exports.MiddlewareProcessor = MiddlewareProcessor;