diff --git a/packages/component/src/loadableReady.js b/packages/component/src/loadableReady.js
index 11e8dedf..689ff37d 100644
--- a/packages/component/src/loadableReady.js
+++ b/packages/component/src/loadableReady.js
@@ -56,7 +56,9 @@ export default function loadableReady(
     function checkReadyState() {
       if (
         requiredChunks.every(chunk =>
-          loadedChunks.some(([chunks]) => chunks.indexOf(chunk) > -1),
+          loadedChunks.some(([chunks]) =>
+            chunks.some(c => String(c) === String(chunk)),
+          ),
         )
       ) {
         if (!resolved) {
diff --git a/packages/component/src/loadableReady.test.js b/packages/component/src/loadableReady.test.js
new file mode 100644
index 00000000..7726ab8f
--- /dev/null
+++ b/packages/component/src/loadableReady.test.js
@@ -0,0 +1,63 @@
+/* eslint-disable no-underscore-dangle */
+import 'regenerator-runtime/runtime'
+import loadableReady from './loadableReady'
+import { LOADABLE_SHARED } from './shared'
+
+beforeEach(() => {
+  document.body.innerHTML = ''
+  delete window.__LOADABLE_LOADED_CHUNKS__
+  LOADABLE_SHARED.initialChunks = {}
+})
+
+function setupRequiredChunks(requiredChunks, namedChunks = []) {
+  const id = '__LOADABLE_REQUIRED_CHUNKS__'
+  const script = document.createElement('script')
+  script.id = id
+  script.type = 'application/json'
+  script.textContent = JSON.stringify(requiredChunks)
+  document.body.appendChild(script)
+
+  const extScript = document.createElement('script')
+  extScript.id = `${id}_ext`
+  extScript.type = 'application/json'
+  extScript.textContent = JSON.stringify({ namedChunks })
+  document.body.appendChild(extScript)
+}
+
+describe('loadableReady', () => {
+  it('should resolve when all string chunks are loaded', async () => {
+    setupRequiredChunks(['letters-A'])
+    window.__LOADABLE_LOADED_CHUNKS__ = [[['letters-A'], []]]
+
+    const done = jest.fn()
+    await loadableReady(done)
+    expect(done).toHaveBeenCalled()
+  })
+
+  it('should resolve when required chunks are numeric and loaded chunks are numeric', async () => {
+    setupRequiredChunks([1, 2])
+    window.__LOADABLE_LOADED_CHUNKS__ = [[[1, 2], []]]
+
+    const done = jest.fn()
+    await loadableReady(done)
+    expect(done).toHaveBeenCalled()
+  })
+
+  it('should resolve when required chunks are string but loaded chunks are numeric', async () => {
+    setupRequiredChunks(['1', '2'])
+    window.__LOADABLE_LOADED_CHUNKS__ = [[[1, 2], []]]
+
+    const done = jest.fn()
+    await loadableReady(done)
+    expect(done).toHaveBeenCalled()
+  })
+
+  it('should resolve when required chunks are numeric but loaded chunks are string', async () => {
+    setupRequiredChunks([1, 2])
+    window.__LOADABLE_LOADED_CHUNKS__ = [[['1', '2'], []]]
+
+    const done = jest.fn()
+    await loadableReady(done)
+    expect(done).toHaveBeenCalled()
+  })
+})
diff --git a/packages/server/src/ChunkExtractor.js b/packages/server/src/ChunkExtractor.js
index 80e95f2b..3f487869 100644
--- a/packages/server/src/ChunkExtractor.js
+++ b/packages/server/src/ChunkExtractor.js
@@ -225,7 +225,9 @@ class ChunkExtractor {
   }
 
   getChunkInfo(chunkId) {
-    const chunkInfo = this.stats.chunks.find(chunk => chunk.id === chunkId)
+    const chunkInfo = this.stats.chunks.find(
+      chunk => String(chunk.id) === String(chunkId),
+    )
     invariant(chunkInfo, `cannot find chunk (chunkId: ${chunkId}) in stats`)
     return chunkInfo
   }
@@ -300,15 +302,17 @@ class ChunkExtractor {
       const chunkGroup = this.getChunkGroup(chunk)
 
       // ignore chunk that only contains css files.
-      return chunkGroup.chunks.filter(chunkId => {
-        const chunkInfo = this.getChunkInfo(chunkId)
+      return chunkGroup.chunks
+        .map(chunkId => String(chunkId))
+        .filter(chunkId => {
+          const chunkInfo = this.getChunkInfo(chunkId)
 
-        if (!chunkInfo) {
-          return false
-        }
+          if (!chunkInfo) {
+            return false
+          }
 
-        return checkIfChunkIncludesJs(chunkInfo)
-      })
+          return checkIfChunkIncludesJs(chunkInfo)
+        })
     }
 
     if (Array.isArray(chunks)) {
diff --git a/packages/server/src/ChunkExtractor.test.js b/packages/server/src/ChunkExtractor.test.js
index 2551235c..ee1625c7 100644
--- a/packages/server/src/ChunkExtractor.test.js
+++ b/packages/server/src/ChunkExtractor.test.js
@@ -929,4 +929,27 @@ describe('ChunkExtrator', () => {
       expect(x.hello).toBe('hello')
     })
   })
+
+  describe('numeric chunk ids', () => {
+    const numericIdStats = {
+      ...stats,
+      chunks: [{ id: 0, files: ['main.css', 'main.js'] }],
+    }
+
+    it('#getChunkInfo should find chunks with numeric ids', () => {
+      const ext = new ChunkExtractor({
+        stats: numericIdStats,
+        outputPath: targetPath,
+      })
+      expect(ext.getChunkInfo(0).id).toBe(0)
+    })
+
+    it('#getChunkInfo should find numeric chunk when given string id', () => {
+      const ext = new ChunkExtractor({
+        stats: numericIdStats,
+        outputPath: targetPath,
+      })
+      expect(ext.getChunkInfo('0').id).toBe(0)
+    })
+  })
 })