import {Directive, Input, ElementRef} from 'angular2/core';
@Directive({
    selector: '[focus]'
})
class FocusDirective {
    @Input()
    focus:boolean;
    constructor(@Inject(ElementRef) private element: ElementRef) {}
    protected ngOnChanges() {
        this.element.nativeElement.focus();
    }
}

// Usage
@Component({
    selector : 'app',
    template : `
        <input [focus]="inputFocused" type="text">
        <button (click)="moveFocus()">Move Focus</button>
    `,
    directives: [FocusDirective]
})
export class App {
    private inputFocused = false;
    moveFocus() {
        this.inputFocused = true;
        // we need this because nothing will
        // happens on next method call,
        // ngOnChanges in directive is only called if value is changed,
        // so we have to reset this value in async way,
        // this is ugly but works
        setTimeout(() => {this.inputFocused = false});
    }
}

import { Directive, ElementRef, Renderer, AfterViewInit } from '@angular/core';
@Directive({
    selector: '[focus]'
})

export class DmFocusDirective implements AfterViewInit {
    constructor(private _el: ElementRef, private renderer: Renderer) {
    }

    ngAfterViewInit() {
        this.renderer.invokeElementMethod(this._el.nativeElement, 'focus');
    }
}

this.renderer.invokeElementMethod(this.input.nativeElement, 'focus', []);

import { Directive, ElementRef, Renderer} from "@angular/core";
@Directive({
    selector: "[Focus]"
})

export class myFocus {
    constructor(private _el: ElementRef, private renderer: Renderer) {
        this.renderer.invokeElementMethod(this._el.nativeElement, 'focus');
    }

}

import {Directive, AfterViewInit, ElementRef, DoCheck} from '@angular/core';

@Directive({selector: '[focus]'})
export class FocusDirective implements AfterViewInit, DoCheck {
    private lastVisible: boolean = false;
    private initialised: boolean = false;

    constructor(private el: ElementRef) {
    }

    ngAfterViewInit() {
        console.log('inside FocusDirective.ngAfterViewInit()');
        this.initialised = true;
        this.ngDoCheck();
    }

    ngDoCheck() {

        console.log('inside FocusDirective.ngDoCheck()');

        if (!this.initialised) {
            return;
        }
        const visible = !!this.el.nativeElement.offsetParent;
        if (visible && !this.lastVisible) {
            setTimeout(() => {
                this.el.nativeElement.focus();
            }, 1);
        }
        this.lastVisible = visible;
    }
}

const element = this.renderer.selectRootElement('#elementId');

element.focus();