Router. EXCEPTION: Expression has changed after it was checked.

[nglazov]

I use [routerLink]="someFunction('Route')"

someFunction(a) {
  return [a]
}

This is example which was taked from docs and was changed just app/app.component.ts.

[wardbell]

While you have definitely found a problem and I believe that what you're trying to do ought to work ... and we're looking into it ... I can't find that example you cite anywhere in the docs. Would you please find that location for me?

[wardbell]

Anyway, the reason you're getting this error now is because, in DevMode (which is the default), Angular runs your fn 2x ... once the normal time, and once again during a check to ensure that you aren't changing things that shouldn't change during the same view-generation pass.

Semantically, you're not changing anything. You're specifying the same route [a] each time.

But technically you're returning a **different array* each time.

The solution (for now) is to run your fn inside your component, capture its value in a component property, and bind to that property instead.

Here's some pseudo-code:

<!-- Template HTML -->
...[RouterLink]="theRoute" ...

// Component
theRoute: RouterLink;
...
theRoute = someFunction(whatever);

[nglazov]

I mean live example from docs.
Yes, i've tried this before and function will be called 10 times (example).

[wardbell]

I searched the code and couldn't find [routerLink]="getLink()". I think I understand the problem. I think you have an old plunker from an earlier version of the doc. If you click the live example link now, you'll get a different result.

The problem is real. But it's not in the router doc. I think we should close this one.

[nglazov]

Oh yeah, it's not from doc. I've forked example and have changed it.
The problem is to use function as input parameter in routerLink directive.

[pkozlowski-opensource]

Same as #6005

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