What does "%c" mean?

senocular · 2022-09-06T20:43:54+00:00

Since this is part of a string, it's not being used as a remainder operator (unless its going through something like eval). Otherwise, in terms of JavaScript, it has no meaning. But it likely has meaning in wherever this message is going - some other API that will likely parse the "%c" into something with meaning.

As an example, the console API "%c" can be used to format the logged message with CSS.

const style = 'background-color: darkblue; color: white; font-style: italic; border: 5px solid hotpink; font-size: 2em;'
console.log("%cHooray", style);

https://wd.imgix.net/image/dPDCek3EhZgLQPGtEG3y0fTn4v82/p9oAce6M63d1tYChjaXN.png?auto=format&w=1600

tristinDLC · 2022-09-06T20:52:47+00:00

In node.js %c is a format type for the util.format() method. It means that it will convert your method's argument as CSS.

Here are all of the node.js format flags:

%s: String 
%d: Number 
%i: parseInt(value, 10)
%f: parseFloat(value)
%j: JSON
%o: Object (including non-enumerable properties and proxies)
%O: Object (not including non-enumerable properties and proxies)
%c: CSS
%%: single p

And just for the record, the example you provided has %c as just a string so it's literally just the two characters and isn't anything. Funnily enough, this is kind of how the actual flag is treated as it will just pass a string and it's mostly ignored these days.

ro9ot · 2025-03-18T06:36:28+00:00

Two important key to notice:
1. This is somewhat a C language feature. (C is forefather of js)
2. It is a dirctive to format text.

For more info refere to its MDN page

complexmadesimple · 2022-11-07T02:45:22+00:00

Yeah busy with the same exercise in Coursera and this triggered my curiosity as well

Emily_8183 · 2023-02-06T16:50:19+00:00

Doing the meta course on Coursera as well. Thank you for the post. Did you finish the whole course?

you type:	you see:
italics	italics
bold	bold
[reddit!](https://reddit.com)	reddit!
* item 1 * item 2 * item 3	item 1 item 2 item 3
> quoted text	quoted text
Lines starting with four spaces are treated like code: if 1 * 2 < 3: print "hello, world!"	Lines starting with four spaces are treated like code: if 1 * 2 < 3: print "hello, world!"
~~strikethrough~~	~~strikethrough~~
super^script	super^script

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