next.js/crates/next-custom-transforms/src/transforms/amp_attributes.rs

use swc_core::ecma::{
    ast::{
        Ident, IdentName, JSXAttr, JSXAttrName, JSXAttrOrSpread, JSXElementName, JSXOpeningElement,
        Pass,
    },
    atoms::Atom,
    visit::{fold_pass, Fold},
};

pub fn amp_attributes() -> impl Pass {
    fold_pass(AmpAttributePatcher::default())
}

#[derive(Debug, Default)]
struct AmpAttributePatcher {}

impl Fold for AmpAttributePatcher {
    fn fold_jsx_opening_element(&mut self, node: JSXOpeningElement) -> JSXOpeningElement {
        let JSXOpeningElement {
            name,
            mut attrs,
            span,
            self_closing,
            type_args,
        } = node;
        let n = name.clone();

        if let JSXElementName::Ident(Ident { sym, .. }) = name {
            if sym.starts_with("amp-") {
                for i in &mut attrs {
                    if let JSXAttrOrSpread::JSXAttr(JSXAttr {
                        name: JSXAttrName::Ident(IdentName { sym, span: s }),
                        span,
                        value,
                    }) = &i
                    {
                        if sym as &str == "className" {
                            *i = JSXAttrOrSpread::JSXAttr(JSXAttr {
                                name: JSXAttrName::Ident(IdentName {
                                    sym: Atom::from("class"),
                                    span: *s,
                                }),
                                span: *span,
                                value: value.clone(),
                            })
                        }
                    }
                }
            }
        }

        JSXOpeningElement {
            name: n,
            attrs,
            span,
            self_closing,
            type_args,
        }
    }
}