unpkg/modules/actions/serveJavaScriptModule.js

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const etag = require("etag");
const babel = require("babel-core");
const getContentTypeHeader = require("../utils/getContentTypeHeader");
const unpkgRewrite = require("../plugins/unpkgRewrite");
function rewriteBareModuleIdentifiers(code, packageConfig) {
const dependencies = Object.assign(
{},
packageConfig.peerDependencies,
packageConfig.dependencies
);
const options = {
// Ignore .babelrc and package.json babel config
// because we haven't installed dependencies so
// we can't load plugins; see #84
babelrc: false,
plugins: [unpkgRewrite(dependencies)]
};
return babel.transform(code, options).code;
}
function serveJavaScriptModule(req, res) {
if (req.entry.contentType !== "application/javascript") {
return res
.status(403)
.type("text")
.send("?module mode is available only for JavaScript files");
}
try {
const code = rewriteBareModuleIdentifiers(
req.entry.content.toString("utf8"),
req.packageConfig
);
res
.set({
"Content-Length": Buffer.byteLength(code),
"Content-Type": getContentTypeHeader(req.entry.contentType),
"Cache-Control": "public, max-age=31536000, immutable", // 1 year
ETag: etag(code),
"Cache-Tag": "file,js-file,js-module"
})
.send(code);
} catch (error) {
console.error(error);
const errorName = error.constructor.name;
const errorMessage = error.message.replace(
/^.*?\/unpkg-.+?\//,
`/${req.packageSpec}/`
);
const codeFrame = error.codeFrame;
const debugInfo = `${errorName}: ${errorMessage}\n\n${codeFrame}`;
res
.status(500)
.type("text")
.send(
`Cannot generate module for ${req.packageSpec}${
req.filename
}\n\n${debugInfo}`
);
}
}
module.exports = serveJavaScriptModule;