esm: change transformSource to load for error

lib/internal/errors.js

@@ -1475,11 +1475,11 @@ E('ERR_INVALID_REPL_EVAL_CONFIG',
 E('ERR_INVALID_REPL_INPUT', '%s', TypeError);
 E('ERR_INVALID_RETURN_PROPERTY', (input, name, prop, value) => {
   return `Expected a valid ${input} to be returned for the "${prop}" from the` +
-         ` "${name}" function but got ${determineSpecificType(value)}.`;
+         ` "${name}" hook but got ${determineSpecificType(value)}.`;
 }, TypeError);
 E('ERR_INVALID_RETURN_PROPERTY_VALUE', (input, name, prop, value) => {
   return `Expected ${input} to be returned for the "${prop}" from the` +
-         ` "${name}" function but got ${determineSpecificType(value)}.`;
+         ` "${name}" hook but got ${determineSpecificType(value)}.`;
 }, TypeError);
 E('ERR_INVALID_RETURN_VALUE', (input, name, value) => {
   const type = determineSpecificType(value);

lib/internal/modules/esm/translators.js

@@ -128,7 +128,7 @@ function assertBufferSource(body, allowString, hookName) {
  */
 function stringify(body) {
   if (typeof body === 'string') { return body; }
-  assertBufferSource(body, false, 'transformSource');
+  assertBufferSource(body, false, 'load');
   const { TextDecoder } = require('internal/encoding');
   DECODER = DECODER === null ? new TextDecoder() : DECODER;
   return DECODER.decode(body);

test/es-module/test-esm-loader.mjs

@@ -43,6 +43,11 @@ await assert.rejects(
   { code: 'ERR_INVALID_RETURN_PROPERTY_VALUE' },
 );
 
+await assert.rejects(import('esmHook/commonJsNullSource.mjs'), {
+  code: 'ERR_INVALID_RETURN_PROPERTY_VALUE',
+  message: /"source".*'load'.*got type bigint/,
+});
+
 await import('../fixtures/es-module-loaders/js-as-esm.js')
 .then((parsedModule) => {
   assert.strictEqual(typeof parsedModule, 'object');

test/fixtures/es-module-loaders/hooks-custom.mjs

@@ -97,5 +97,13 @@ export function load(url, context, next) {
     };
   }
 
+  if (url.endsWith('esmHook/commonJsNullSource.mjs')) {
+    return {
+      format: 'commonjs',
+      shortCircuit: true,
+      source: 1n,
+    };
+  }
+
   return next(url);
 }