code-loader.js

const blockLoader = require('block-loader');

const options = {
	start: '<pre><code className="javascript">',
	end: '</code></pre>',
	process: function fixPreBlocks(pre) {
		const replaced = pre
			.replace(options.start,'')   // first, remove the start/end delimiters, then:
			.replace(options.end,'')     //
			.replace(/&/g,'&amp;')       // 1. use html entity equivalent,
			.replace(/</g,'&lt;')        // 2. use html entity equivalent,
			.replace(/>/g,'&gt;')        // 3. use html entity equivalent,
			.replace(/\t/g, '    ')
			.replace(/([{}])/g,"{'$1'}") // 4. JSX-safify curly braces,
			.replace(/\n/g,"{'\\n'}");   // 5. and preserve line endings, thanks.

		// done! return with the delimiters put back in place
		return options.start + replaced + options.end
	}
};
module.exports = blockLoader(options)