A syntax highlighting block for Gutenberg with custom themes for every languages.
Add a Code Block, paste your code, select the language in the inspector, add a file name (optionnal). Choose if you want to display line number, define a line start number and that’s it!
Performances: WordPress only loads in front the minimum scripts/styles required according to languages used in the post.
This block uses Code Mirror and React Code Mirror from Marijn Haverbeke and Jed Watson.