Hide/Show navigation button not worked in angular 5

[mirajehossain]

[showPrev]="step1.showPrev" [showNext]="step1.showNext" not worked in angular 5
Always shows previous, next, done button.

here is my component code
step1: any = { showNext: true, showPrev: false };

my angular cli version:
"@angular/cli": "1.6.0",
angular version
"@angular/core": "^5.0.0",