Notes, summaries, assignments, exams, and exercises for Technology for Vocational training

Custom Call, Apply, and Bind Implementations

In JavaScript, Function.prototype.call, apply, and bind allow developers to explicitly set execution context (the this value). Below are custom implementations (polyfills) for these methods.

1. Custom Call Polyfill (myCall)

The myCall method invokes a function with a specified context and arguments passed individually:

if (!Function.prototype.myCall) {
    Function.prototype.myCall = function(thisArg, ...args) {
        if (typeof this !== "function") {
            throw new TypeError(`${thisArg} can only be used on functions`);
        }

        const context = thisArg || window;
        context.fn = this;

        return thisArg.fn(...args);
    };
}

2. Custom Apply Polyfill (myApply)

The myApply method...

X.25 Networks

X.25 is a standard for wide area network (WAN) packet switching. It establishes mechanisms for routing between users, negotiation of communication features, and error recovery techniques. Public packet-switching services support numerous types of stations from different manufacturers. Therefore, it is of utmost importance to define the interface between the end user's computer and the network.

Levels of X.25

• Physical Level: The recommendation for the X.25 packet level coincides with one of the recommendations of the third level of the OSI model. X.25 encompasses the third level and also the two lowest levels.
• The Link Layer: In X.25, it is assumed that the link layer is LAPB (Link Access Procedure, Balanced). LAPB is responsible for