Can I have TypeScript's compiled JavaScript check types?

Question

I've run my code through tsc, and have the following output for a constructor function accepting a single string parameter:

function Session(endpoint) {
    var _this = this;
    _super.call(this);
    this.endpoint = endpoint;

There's no check that the parameter is defined or that typeof(endpoint) === "string".

Are these checks only made at compile time? I originally had some sanity checks in the constructor to ensure that the value was correct, then deleted them because I assumed tsc would output them. Type declarations will certainly be useful when compiling, but I was hoping for runtime checks as well, and hoping not to have to write all that boilerplate.

Thanks.

Alex · Accepted Answer · 2016-04-13 14:00:18Z

3

No. Typescript does not have runtime type checks.

A proposition to include this in the language was declined with a reference to their design goals.

answered Apr 13, 2016 at 14:00

Alex

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Nolan · Accepted Answer · 2016-04-13 14:03:56Z

1

Should have known to post a question before my first cup of coffee. Googling "typescript runtime type checks" gave me the answer:

It is apparently outside of TS' goals but there is an NPM package that does it.

answered Apr 13, 2016 at 14:03

Nolan

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