jsguide: Explain more - Infer Templatized type/ template parameter, but not its parameters

https://google.github.io/styleguide/jsguide.html#features-declare-types-as-needed

Tip: There are many cases where the compiler can infer a templatized type but not its parameters. This is particularly the case when the initializing literal or constructor call does not include any values of the template parameter type (e.g., empty arrays, objects, Maps, or Sets), or if the variable is modified in a closure. Local variable type annotations are particularly helpful in these cases since otherwise the compiler will infer the template parameter as unknown.

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- "Infer Templatized type/ template parameter, but not its parameters"