Differences between value and ngValue in Angular 5

Question

Today I realized about an unexpected (for me) behaviour of the reactive forms in Angular 5. The server was receiving from the app an string with the value "null" i

Answer 1

const items = ["foo", "bar", "baz"]

    {{item}}

using [value] when one of the options is selected the value will be foo, bar, baz

    {{item}}

using [ngValue] when one of the options is selected the value will be 0: foo, 1: bar, 2: baz