svelte/test/setup.js

const fs = require('fs');

require('source-map-support').install();

process.env.TEST = 'true';

require.extensions['.js'] = function (module, filename) {
	const exports = [];

	let code = fs
		.readFileSync(filename, 'utf-8')
		.replace(/^import \* as (\S+) from ['"]([^'"]+)['"];?/gm, 'var $1 = require("$2");')
		.replace(/^import {([^}]+)} from ['"](.+)['"];?/gm, 'var {$1} = require("$2");')
		.replace(
			/^import (\S+),\s+?{([^}]+)} from ['"](.+)['"];?/gm,
			'var {default: $1, $2} = require("$3");'
		)
		.replace(/^import (\S+) from ['"]([./][^'"]+)['"];?/gm, 'var {default: $1} = require("$2");')
		.replace(/^import (\S+) from ['"]([^'"]+)['"];?/gm, 'var $1 = require("$2");')
		.replace(/^export default /gm, 'exports.default = ')
		.replace(
			/^export (const|let|var|class|function|async\s+function) (\w+)/gm,
			(match, type, name) => {
				exports.push(name);
				return `${type} ${name}`;
			}
		)
		.replace(/^export \{([^}]+)\}(?: from ['"]([^'"]+)['"];?)?/gm, (match, names, source) => {
			names
				.split(',')
				.filter(Boolean)
				.forEach((name) => {
					exports.push(name);
				});

			return source ? `const { ${names} } = require("${source}");` : '';
		})
		.replace(/^export function (\w+)/gm, 'exports.$1 = function $1');

	exports.forEach((name) => {
		code += `\nexports.${name} = ${name};`;
	});

	try {
		return module._compile(code, filename);
	} catch (err) {
		console.log(code); // eslint-disable-line no-console
		throw err;
	}
};