Property '...' is declared but never used

Question

I have many unused params for my functions and constructors, usualy, an underscore does the trick

1) but here I still get the error message

I tried this (or adding an underscore)

/* tslint:disable-next-line:no-unused-variable */
constructor(private el: ElementRef) {  }

with no luck

2) how do we deal with parameters that are only used in the templates, such errors will be triggered ?

I have to console.log to faint using a variable

thanks

Answer 1

Just set your variable as public

constructor(public el: ElementRef) {  }

Source : https://github.com/palantir/tslint/issues/3094

Answer 2

There are could be two reason for this tslint error(Property '…' is declared but never used )

1. Either variable is getting used in HTML in that case to fixed it use public

   constructor(public el: ElementRef) { }

2. If variable is getting used only in constructor, hence without this keyword to fix this use just remove public/private

   constructor(el: ElementRef) { }

When we inject this way we will not be able to use it in class other than constructor.

I got very good explanation from Constructor params used without the "this." are marked as unused. and stop-manually-assigning-typescript-constructor-parameters