Skip to content

doc: clarify behavior of byteLength with 'base64' #11238

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Feb 9, 2017
Merged

doc: clarify behavior of byteLength with 'base64' #11238

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 4 additions & 0 deletions doc/api/buffer.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -618,6 +618,10 @@ Returns the actual byte length of a string. This is not the same as
[`String.prototype.length`] since that returns the number of *characters* in
a string.

*Note* that for `'base64'` and `'hex'`, this function assumes valid input. For
strings that contain non-Base64/Hex-encoded data (e.g. whitespace), the return
value might be greater than the length of a `Buffer` created from the string.
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

The return value could be smaller too (e.g. Buffer.byteLength('1345 4 ', 'hex') === 3, Buffer.from('1345 4 ').byteLength === 7), but then since the data is invalid it's just hard to say. Maybe just say something like the return value is meaningless and should not be used?

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Hmm, wait, I forgot to pass hex to Buffer.from('1345 4 '), that one would just throws TypeError: Invalid hex string, so there is nothing to compare :/

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Yeah, logically there is no way for it to be smaller. That would imply that you can encode more data by using an invalid string than a valid string.

It's not completely meaningless - e.g. if you allocate a Buffer with the size at least Buffer.byteLength, then the actual buffer will fit in it. Although I can't imagine a use case for it.


Example:

```js
Expand Down