typescript3.ts

namespace Structure {
    export interface Tab {
        preload(callback: () => void): void;
        execute(): void;
        build(set: Array<Structure.Person>): boolean;
        built(): boolean;
    }
}

class Impact implements Structure.Tab {
    constructor() {
        // ...
    }
    
    public preload(callback: () => void): void {
        // ...
        callback();
    }
    
    public execute(): void {
        // ...
    }
    
    public build(set: Array<Structure.Person>): boolean {
        // ...
        
        return true;
    }
    
    public built(): boolean {
        // ...
        
        return true;
    }
    
    // ...
}