Back button in Product details page not working

[ApoTheOne]

On Click of back button in product detail button, this exception occurs:

[object Error]: {description: "Object doesn't support property or method 'onBack'", message: "Object doesn't support property or method 'onBack'", ngDebugContext: Object, ngErrorLogger: function() { [native code] }, number: -2146827850...}
description: "Object doesn't support property or method 'onBack'"
message: "Object doesn't support property or method 'onBack'"

ngDebugContext: Object

ngErrorLogger: function() { [native code] }
number: -2146827850
stack: "TypeError: Object doesn't support property or method 'onBack' at Anonymous function (Function code:77:11) at handleEvent (eval code:13778:87) at callWithDebugContext (eval code:15287:9) at debugHandleEvent (eval code:14874:5) at dispatchEvent (eval code:10191:9) at Anonymous function (eval code:10812:31) at Anonymous function (eval code:2679:9) at ZoneDelegate.prototype.invokeTask (eval code:423:13) at onInvokeTask (eval code:4943:17) at ZoneDelegate.prototype.invokeTask (eval code:423:13)"

[ApoTheOne]

Missed function in the component, adding it back fixed this issue.