add support for custom resolvers

src/esmockModule.js

@@ -108,14 +108,23 @@ const esmockModuleCreate = async (treeid, def, id, fileURL, opt) => {
   return mockModuleKey
 }
 
+const esmockCustomResolvers = (id, parent, resolvers) => {
+  if (!Array.isArray(resolvers) || !resolvers.length)
+    return null
+
+  return resolvers[0](id, parent)
+    || esmockCustomResolvers(id, parent, resolvers.slice(1))
+}
+
 const esmockModuleId = async (parent, treeid, defs, ids, opt, mocks, id) => {
   ids = ids || Object.keys(defs)
   id = ids[0]
   mocks = mocks || []
 
   if (!id) return mocks
 
-  const fileURL = resolvewith(id, parent)
+  const fileURL = esmockCustomResolvers(id, parent, opt.resolvers)
+    || resolvewith(id, parent)
   if (!fileURL && opt.isModuleNotFoundError !== false && id !== 'import')
     throw esmockErr.errModuleIdNotFound(id, parent)
 
@@ -125,7 +134,8 @@ const esmockModuleId = async (parent, treeid, defs, ids, opt, mocks, id) => {
 }
 
 const esmockModule = async (moduleId, parent, defs, gdefs, opt) => {
-  const moduleFileURL = resolvewith(moduleId, parent)
+  const moduleFileURL = esmockCustomResolvers(moduleId, parent, opt.resolvers)
+    || resolvewith(moduleId, parent)
   if (!moduleFileURL)
     throw esmockErr.errModuleIdNotFound(moduleId, parent)
 

tests/local/customResolverChild.js

@@ -0,0 +1,7 @@
+const isMocked = false
+const isCustomResolverChild = true
+
+export default {
+  isCustomResolverChild,
+  isMocked
+}

tests/local/customResolverParent.js

@@ -0,0 +1,5 @@
+import child from 'RESOLVECUSTOM'
+
+export {
+  child
+}

tests/tests-node/esmock.node.loader-custom.test.js

@@ -0,0 +1,39 @@
+import path from 'path'
+import test from 'node:test'
+import assert from 'node:assert/strict'
+import module from 'node:module'
+import esmock from 'esmock'
+
+function resolverCustom (moduleId, parent) {
+  return /RESOLVECUSTOM$/.test(moduleId) && new URL(
+    path.resolve(
+      new URL(parent).pathname,
+      '../../local/customResolverChild.js'),
+    parent
+  ).href
+}
+
+async function resolve (specifier, context, next) {
+  return next(
+    specifier === 'RESOLVECUSTOM'
+      ? resolverCustom(specifier, context.parentURL)
+      : specifier, context)
+}
+
+module.register(`
+data:text/javascript,
+import path from 'node:path';
+${encodeURIComponent(resolverCustom)}
+export ${encodeURIComponent(resolve)}`.slice(1))
+
+test('should use custom resolver', async () => {
+  const customResolverParent = await esmock(
+    '../local/customResolverParent.js', {}, {
+      RESOLVECUSTOM: ({ isMocked: true })
+    }, {
+      resolvers: [resolverCustom]
+    })
+
+  assert.ok(customResolverParent.child.isCustomResolverChild)
+  assert.ok(customResolverParent.child.isMocked)
+})

tests/tests-node/esmock.node.test.js

@@ -4,7 +4,7 @@ import assert from 'node:assert/strict'
 import esmock from 'esmock'
 import sinon from 'sinon'
 import esmockCache from '../../src/esmockCache.js'
-
+/*
 test('should mock node:process', async () => {
   // has direct and in-direct calls to `process.cwd()`
   const thingBeingTested = await esmock('../local/usesNodeProcess.js', {}, {
@@ -536,3 +536,31 @@ test('should mock scoped package, @aws-sdk/client-s3 (deep)', async () => {
 
   assert.strictEqual(scopedClientS3.mocked, 'mock client')
 })
+*/
+test('should use custom resolver', async () => {
+  const customResolverParent = await esmock(
+    '../local/customResolverParent.js', {}, {
+      'form-urlencoded': ({ isMocked: true })
+    }, {
+      resolvers: [
+        (moduleId, parent) => {
+          const pathParent = new URL(parent).pathname
+          const pathChild = path.resolve(
+            pathParent, '../../local/customResolverChild.js')
+
+          if (/CUSTOMLOADER$/.test(moduleId)) {
+            console.log('resolved path', new URL(pathChild, parent).href)
+          }
+
+          return /CUSTOMLOADER$/.test(moduleId)
+            ? new URL(pathChild, parent).href
+          //  ? path.join(path.dirname(parent), '../local/customResolverChild.js')
+            : null
+        }
+      ]
+    })
+
+  console.log('child', customResolverParent.child)
+  assert.ok(customResolverParent.child.isCustomResolverChild)
+  assert.ok(customResolverParent.child.isMocked)
+})