feat: add svelte2 rollup loader

Author: tivac

rollup/svelte2.js

@@ -0,0 +1,45 @@
+const svelte = require("svelte2");
+const { createFilter } = require("rollup-pluginutils");
+
+const defaults = {
+    include    : [ /\.html$/ ],
+    exclude    : [ "**/node_modules/**" ],
+    preprocess : false,
+    options    : {
+        format : "es",
+    },
+};
+
+module.exports = (args = {}) => {
+    const options = {
+        ...defaults,
+        ...args,
+    };
+
+    const filter = createFilter(options.include, options.exclude);
+
+    return {
+        name : "svelte-translator-rollup-svelte2",
+
+        async transform(code, filename) {
+            if(!filter(filename)) {
+                return null;
+            }
+
+            // const { code : processed, dependencies } = await options.preprocess ?
+            const result = options.preprocess ?
+                await svelte.preprocess(code, options.preprocess, { filename }) :
+                await Promise.resolve({ toString : () => code });
+
+            const { js } = svelte.compile(result.toString(), {
+                onwarn : (warning) => this.warn(warning),
+                
+                ...options.options,
+                
+                filename,
+            });
+
+            return js;
+        },
+    };
+};