trackBy must be a function, but received null

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**Current behavior**
I'm using the exact example code from the docs...
https://swimlane.gitbooks.io/ngx-datatable/content/introduction/getting-started.html

But when I run it, I'm getting this error:
Error: trackBy must be a function, but received null
    at NgFor.set [as ngForTrackBy] (ng_for.js:151) [angular]


**Expected behavior**
Should display the simple table

**Reproduction of the problem**
Typescript: 2.0.10
angular-cli: 1.0.0-beta.24
node: 6.9.1
os: win32 x64
@angular/common: 2.4.1
@angular/compiler: 2.4.1
@angular/core: 2.4.1
@angular/forms: 2.4.1
@angular/http: 2.4.1
@angular/material: 2.0.0-alpha.11-3
@angular/platform-browser: 2.4.1
@angular/platform-browser-dynamic: 2.4.1
@angular/router: 3.4.1
@angular/compiler-cli: 2.4.1

[DzmitryShylovich]

https://github.com/swimlane/ngx-datatable/blob/master/src/components/body/body-row.component.ts#L18 incorrect usage of trackBy, for example. it’s not an angular issue 😃

[josh-sachs]

@amcdnl yes - previously you could do

trackBy: item?.Id

or

trackBy: trackByFn

it’s documented that way all over the place… e.g. http://stackoverflow.com/questions/36322829/how-to-use-track-by-inside-ngfor-angular-2

I know that specific example is before 2.0.0 BUT I was using trackBy this way until at least 2.2.3 (I just upgraded to 2.4.1 and it now only accepts a function and will throw with the syntax in the first example).