Constructor parameter property declaration

[dariajung]

Parameter properties need to be desguared, or handled otherwise:

class Animal {
    constructor(private name: string) { 
        console.log(name);
    }
}

is sugar for

class Animal {
    private name: string;
    constructor(name: string) { 
        this.name = name;
    }
}

name is a property that, if renamed in the parameter property declaration, also needs to be renamed in the constructor body if used.

[dariajung]

Duplicate of #39. Moving comments over.