Parse data: URLs
This package helps you parse data:
URLs according to the WHATWG Fetch Standard:
API
This package's main module's default export is a function that accepts a string and returns a { mimeType, body }
object, or null
if the result cannot be parsed as a data:
URL.
The
mimeType
property is an instance of whatwg-mimetype'sMIMEType
class.The
body
property is a Node.jsBuffer
instance.
As shown in the examples above, both of these have useful toString()
methods for manipulating them as string values. However…
A word of caution on string decoding
Because Node.js's Buffer.prototype.toString()
assumes a UTF-8 encoding, simply doing dataURL.body.toString()
may not work correctly if the data:
URL's contents were not originally written in UTF-8. This includes if the encoding is "US-ASCII", aka windows-1252, which is notable for being the default in many cases.
A more complete decoding example would use the whatwg-encoding package as follows:
For example, given an arbitraryString
of data:,Hello!
, this will produce a bodyDecoded
of "Hello!"
, as expected. But given an arbitraryString
of "data:,Héllo!"
, this will correctly produce a bodyDecoded
of "Héllo!"
, whereas just doing dataURL.body.toString()
will give back "Héllo!"
.
In summary, only use dataURL.body.toString()
when you are very certain your data is inside the ASCII range (i.e. code points within the range U+0000 to U+007F).
Advanced functionality: parsing from a URL record
If you are using the whatwg-url package, you may already have a "URL record" object on hand, as produced by that package's parseURL
export. In that case, you can use this package's fromURLRecord
export to save a bit of work:
In practice, we expect this functionality only to be used by consumers like jsdom, which are using these packages at a very low level.
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