How can I distinguish typescript from javascript by looking at the source code?

Question

I am inspecting some code on Github and I need to quickly understand if the script is javascript or typescript.

Are there any easy shortcuts or clues to this?

As an example, in this image from https://www.typescriptlang.org/ gives me a clue that if an array is declared with a bracket [] after the variable name, then it is typescript.

thanks, how about Javascript, is it Javascript if the extension is .js ? — eugen
– eugen, Commented Mar 23, 2020 at 0:36

Anthony Moon Beam Toorie · Accepted Answer · 2020-03-23 00:39:45Z

1

You can distinguish between the two formats by looking simply at the functions.

Are any of the functions specifying types such as 'string,integer,object,array,function?...' etc?

In traditionally javascript this is not allowed.

Best, AT

Also as others may have pointed out, you can also check the file extension

answered Mar 23, 2020 at 0:39

Anthony Moon Beam Toorie

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2 Comments

eugen Over a year ago

so in contemporary javascript 'string,integer,object,array,function?...' is allowed?

Anthony Moon Beam Toorie Over a year ago

They are but the language is not explicity typed. They are implicitly referred to by the contents or by other means. On the right hand side you may see new Arrays() or whatever but on the left side (assignment) there will be no declared type. The variable just get what it asks for

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