Unable to add property to an existing object in Javascript with Visual Studio Code

Question

I'm trying some simple Javascript in the new Visual Studio Code. With the following js code:

var obj = { abc: "test" };
obj.foo = "bar";

I get this error:

Property 'foo' does not exist on type '{ abc: string; }'.

However it's a js file rather than ts. Isn't the code valid in Javascript?

interesting, it works fine for me in a js file – John Papa Apr 30 '15 at 07:24 — John Papa, Apr 30 '15 at 07:24
This issue appears on my friend's vscode too. – Bruce55 Apr 30 '15 at 07:28 — Bruce55, Apr 30 '15 at 07:28
@utility simple javascript file. – Bruce55 Apr 30 '15 at 07:40 — Bruce55, Apr 30 '15 at 07:40

score 2 · Answer 1 · edited May 23 '17 at 12:14

2

This is actually by design. It may be considered valid JavaScript, but it is not valid TypeScript Syntax.

See How do I dynamically assign properties to an object in TypeScript?, http://typescript.codeplex.com/workitem/1657, and http://typescript.codeplex.com/discussions/397908.

The good news is, JavaScript isn't compiled, so the file will still work correctly on your client, as tsc.exe will never really be run against the .js file.

edited May 23 '17 at 12:14

Community

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answered Apr 30 '15 at 07:41

Claies

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Correct, from the video on https://code.visualstudio.com/, Code uses TypeScript under the hood to *verify* all Javascript. – CodingIntrigue Apr 30 '15 at 09:27

score 0 · Answer 2 · answered Apr 30 '15 at 10:47

0

There is a rule to configure how these situation are handled. The default should be ignore in JavaScript but you can configure it to be a warning or an error with this:

{
    "javascript.validate.lint.unknownProperty": "ignore"
}

answered Apr 30 '15 at 10:47

Johannes Rieken

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Unable to add property to an existing object in Javascript with Visual Studio Code

2 Answers2