TypeScript Language Specification v1.5

Initializer expressions for instance member variables are evaluated in the scope of the class constructor
body but are not permitted to reference parameters or local variables of the constructor. This effectively
means that entities from outer scopes by the same name as a constructor parameter or local variable are
inaccessible in initializer expressions for instance member variables.
Since instance member variable initializers are equivalent to assignments to properties of this in the
constructor, the example
class Employee {
public name: string;
public address: string;
public retired = false;
public manager: Employee = null;
public reports: Employee[] = [];
}
is equivalent to
class Employee {
public name: string;
public address: string;
public retired: boolean;
public manager: Employee;
public reports: Employee[];
constructor() {
this.retired = false;
this.manager = null;
this.reports = [];
}
}
8.4.2 Member Function Declarations
A member function declaration declares an instance member function or a static member function.
MemberFunctionDeclaration:
MemberFunctionOverloads opt MemberFunctionImplementation
MemberFunctionOverloads:
MemberFunctionOverload
MemberFunctionOverloads MemberFunctionOverload
MemberFunctionOverload:
AccessibilityModifier opt static opt PropertyName CallSignature ;
MemberFunctionImplementation:
AccessibilityModifier opt static opt PropertyName CallSignature { FunctionBody }
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