Why does the ngFor-TrackBy html extension create a "item.id" and not use a function call?

[Chewieez]

vscode-angular-snippets/snippets/html.json

Line 24 in c010f9e

"body": ["*ngFor=\"let ${1:item} of ${2:list}; trackBy:${1:item}.id\"${0}"],

This code above is the line in question. I am using the Angular snippets to speed up ngFor TrackBy usage. I first saw the extension in my .html file but Angular showed an error that it didn't know the value of item in trackBy: item.id. After researching I saw it appears the trackBy should call a function and not be assigned to a property of item. Then I found the a-trackby extension in the .ts file to create a trackBy function. Should these 2 extensions (the html and ts) ones work together? Should the html extension create this markup instead
*ngFor="let item of list; trackBy: trackBy"?

[johnpapa]

good question, im not aware of how they can be. any ideas?