Namespaces and modules versus typing in typescript?

Question

Can someone please explain the difference between these concepts with an example, am I really confused that using three of them when they all serve the same purpose?

Answer 1

TL DR

Modules and namespaces are two means of encapsulation - breaking code into pieces that make sense. New code should be written using modules, not namespaces.

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namespace foo {
    export var x = 10;
    export var y = 20;
}

var foo;
(function (foo) {
    foo.x = 10;
    foo.y = 20;
})(foo || (foo = {}));

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export var x = 10;
export var y = 20;

CommonJS:

"use strict";
Object.defineProperty(module.exports, "__esModule", { value: true });
module.exports.x = 10;
module.exports.y = 20;

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    return x * 100 + y;
}

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declare function foo(x: number, y: number): number

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