Why push shows argument of type 'any[]' is not assignable to parameter of type 'never' error?

Question

In this code i get the fallowing error:

Argument of type 'any[]' is not assignable to parameter of type 'never'

var markers: [];
this.Getlapoints(this.map.getCenter(), 500000).then(data => {
  for (var key in data) {
    Leaflet.marker(data[key].location, //{ icon: greenIcon            }
    ).addTo(this.map).bindPopup(data[key].caption);
    // markers.push(data[key].location.lat,data[key].location.lng);
    // markers.push(data[key].location);

    var lat = data[key].location.lat;
    var lng = data[key].location.lng;
    markers.push([lat, lng]);
  }
  console.log(markers);
});

score 64 · Answer 1 · answered May 31 '19 at 11:56

64

Change this :

const a = [];

By this :

const a = Array();

answered May 31 '19 at 11:56

Denis TRUFFAUT

1,017
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11

I believe this should be made as the accepted answer ! – Amitya Narayan Feb 14 '23 at 17:11

score 50 · Accepted Answer · answered Aug 28 '18 at 13:33

50

With var markers: [] you are declaring the markers array as having the type of a permanently empty array. You probably meant var markers = [] to initialize it to empty but allow items to be added.

answered Aug 28 '18 at 13:33

Matt McCutchen

28,856
2
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14

thanks, this is the answer to my problem, but I was only able to surmount it like this: `let all: any[] = []` – JP Lew Apr 24 '19 at 22:52

score 7 · Answer 3 · answered Apr 27 '21 at 01:11

7

In tsconfig.json -

 "noImplicitReturns": false,

 "strictNullChecks":false,

Solution: type as 'never'

answered Apr 27 '21 at 01:11

rohit.khurmi095

2,203
1
14
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Turning off the check is not a fix – JG3 Jun 08 '23 at 15:08

score 1 · Answer 4 · answered Aug 28 '18 at 09:20

1

The never type is a subtype of, and assignable to, every type; however, no type is a subtype of, or assignable to, never (except never itself). Even any isn’t assignable to never.

From the TypeScript docs

answered Aug 28 '18 at 09:20

Programmer

1,973
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I don't what are you suppose to do. You can replace the `never` with `null` or empty string or 'never' (as string). – Programmer Aug 28 '18 at 09:47
I want to store all posts latlang in array to use in leaflet, LatLngBounds to fit all markers in map view. – Parsaria Aug 28 '18 at 13:02

Why push shows argument of type 'any[]' is not assignable to parameter of type 'never' error?

4 Answers4