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Classes & Objects

Ayesha
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TypeScript features comprehensive Object-Oriented structures, adding strict encapsulation modifiers and type properties over traditional JavaScript classes.

Video Explanation​

1. Class Structure and Properties​

class NetworkDevice {
    // Explicit field type definitions
    public deviceId: number;
    public deviceModel: string;

    // Execution constructor method configuration
    constructor(id: number, model: string) {
        this.deviceId = id;
        this.deviceModel = model;
    }

    public syncTelemetry(): void {
        console.log(`Syncing tracking nodes for device ${this.deviceId}.`);
    }
}

// Instantiating concrete object allocations
const gatewayRouter = new NetworkDevice(881, "Cisco ISR");
gatewayRouter.syncTelemetry();

2. Property Encapsulation Access Modifiers​

TypeScript provides three explicit visibility modifiers to protect class properties from unintended external modifications:

  • public: (Default) Properties can be accessed from any file or outer runtime context.
  • private: Access is strictly confined to the defining class boundary itself.
  • protected: Access is shared with subclasses inheriting from this parent class.
class BankVault {
    public vaultLabel: string;
    private combinationSequence: number[];
    protected emergencyOverrideToken: string;

    constructor(label: string, combination: number[], token: string) {
        this.vaultLabel = label;
        this.combinationSequence = combination;
        this.emergencyOverrideToken = token;
    }
}

3. Parameter Properties (Shorthand Syntax)​

You can compress constructor logic by declaring visibility access modifiers directly inside the arguments signature list. This tells the compiler to automatically declare and assign those fields for you:

class CompressedUser {
    // Declares, initializes, and maps fields completely in one line
    constructor(public username: string, private accessLevel: number) {}
}
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