better error for incorrect import specifiers

Author: Guy Bedford

src/componentize.js

@@ -134,6 +134,10 @@ export async function componentize(jsSource, witWorld, opts) {
     curIdx = 0;
   for (const jsImpt of jsImports) {
     if (jsImpt.t !== 1 && jsImpt.t !== 2) continue;
+    if (!jsImpt.n) continue;
+    if (!imports.some(([impt]) => jsImpt.n === impt)) {
+      throw new Error(`Import '${jsImpt.n}' is not defined by the WIT world. Make sure to use a bundler for JS dependencies such as esbuild or RollupJS. Future ComponentizeJS versions may include Node.js builtins and bundling.`);
+    }
     const specifier = jsSource.slice(jsImpt.s, jsImpt.e);
     source += jsSource.slice(curIdx, jsImpt.s);
     source += `./${specifier.replace(':', '__').replace('/', '$')}.js`;

test/cases/bad-binding/source.js

@@ -0,0 +1 @@
+import blah from 'not:world-defined';

test/cases/bad-binding/test.js

@@ -0,0 +1,5 @@
+import { strictEqual } from 'node:assert';
+
+export function err (error) {
+  strictEqual(error.message, "Import 'not:world-defined' is not defined by the WIT world. Make sure to use a bundler for JS dependencies such as esbuild or RollupJS. Future ComponentizeJS versions may include Node.js builtins and bundling.");
+}

test/cases/bad-binding/world.wit

@@ -0,0 +1,12 @@
+package local:%char;
+
+interface chars {
+  /// A function that returns a character
+  return-char: func() -> char;
+  /// A function that accepts a character
+  take-char: func(x: char);
+}
+
+world the-world {
+  import chars;
+}