feat(filters): Add base64_encode and base64_decode filters for Shopify compatibility (#828)

* feat(filters): add base64 encode and decode

* fix: use Object.defineProperty for cross-platform btoa/atob mocking

* docs(filters): update docs

* docs(filters): update version

src/build/base64-impl-browser.spec.ts

@@ -0,0 +1,101 @@
+import * as base64 from './base64-impl-browser'
+import { JSDOM } from 'jsdom'
+
+describe('base64-impl/browser', function () {
+  if (+(process.version.match(/^v(\d+)/) as RegExpMatchArray)[1] < 8) {
+    console.info('jsdom not supported, skipping base64-impl-browser...')
+    return
+  }
+
+  beforeEach(function () {
+    const dom = new JSDOM(``, {
+      url: 'https://example.com/',
+      contentType: 'text/html',
+      includeNodeLocations: true
+    })
+
+    // Mock btoa and atob on global object
+    Object.defineProperty(global, 'btoa', {
+      value: dom.window.btoa,
+      writable: true,
+      configurable: true
+    })
+    Object.defineProperty(global, 'atob', {
+      value: dom.window.atob,
+      writable: true,
+      configurable: true
+    })
+  })
+
+  afterEach(function () {
+    delete (global as any).btoa
+    delete (global as any).atob
+  })
+
+  describe('#base64Encode()', function () {
+    it('should encode a simple string', function () {
+      expect(base64.base64Encode('one two three')).toBe('b25lIHR3byB0aHJlZQ==')
+    })
+
+    it('should encode an empty string', function () {
+      expect(base64.base64Encode('')).toBe('')
+    })
+
+    it('should encode a string with special characters', function () {
+      expect(base64.base64Encode('Hello, World! @#$%')).toBe('SGVsbG8sIFdvcmxkISBAIyQl')
+    })
+
+    it('should encode numeric strings', function () {
+      expect(base64.base64Encode('123')).toBe('MTIz')
+    })
+
+    it('should encode boolean strings', function () {
+      expect(base64.base64Encode('true')).toBe('dHJ1ZQ==')
+    })
+  })
+
+  describe('#base64Decode()', function () {
+    it('should decode a simple string', function () {
+      expect(base64.base64Decode('b25lIHR3byB0aHJlZQ==')).toBe('one two three')
+    })
+
+    it('should decode an empty string', function () {
+      expect(base64.base64Decode('')).toBe('')
+    })
+
+    it('should decode a string with special characters', function () {
+      expect(base64.base64Decode('SGVsbG8sIFdvcmxkISBAIyQl')).toBe('Hello, World! @#$%')
+    })
+
+    it('should decode numeric strings', function () {
+      expect(base64.base64Decode('MTIz')).toBe('123')
+    })
+
+    it('should decode boolean strings', function () {
+      expect(base64.base64Decode('dHJ1ZQ==')).toBe('true')
+    })
+  })
+
+  describe('round-trip encoding/decoding', function () {
+    it('should encode and decode back to original', function () {
+      const original = 'Hello, World!'
+      const encoded = base64.base64Encode(original)
+      const decoded = base64.base64Decode(encoded)
+      expect(decoded).toBe(original)
+    })
+
+    it('should handle complex strings with special characters', function () {
+      const original = 'Special chars: !@#$%^&*()_+-=[]{}|;:,.<>?'
+      const encoded = base64.base64Encode(original)
+      const decoded = base64.base64Decode(encoded)
+      expect(decoded).toBe(original)
+    })
+
+    it('should handle mixed unicode and ASCII', function () {
+      const original = 'Hello 🌍'
+      const encoded = base64.base64Encode(original)
+      const decoded = base64.base64Decode(encoded)
+      expect(decoded).toBe(original)
+    })
+  })
+})

src/build/base64-impl-browser.ts

@@ -0,0 +1,10 @@
+
+export function base64Encode (str: string): string {
+  return btoa(String.fromCharCode(...new TextEncoder().encode(str)))
+}
+
+export function base64Decode (str: string): string {
+  return new TextDecoder().decode(
+    Uint8Array.from(atob(str), c => c.charCodeAt(0))
+  )
+}

src/filters/base64-impl.ts

@@ -0,0 +1,7 @@
+export function base64Encode (str: string): string {
+  return Buffer.from(str, 'utf8').toString('base64')
+}
+
+export function base64Decode (str: string): string {
+  return Buffer.from(str, 'base64').toString('utf8')
+}

src/filters/base64.ts

@@ -0,0 +1,21 @@
+/**
+ * Base64 related filters
+ *
+ * Implements base64_encode and base64_decode filters for Shopify compatibility
+ */
+
+import { FilterImpl } from '../template'
+import { stringify } from '../util'
+import { base64Encode, base64Decode } from './base64-impl'
+
+export function base64_encode (this: FilterImpl, value: string): string {
+  const str = stringify(value)
+  this.context.memoryLimit.use(str.length)
+  return base64Encode(str)
+}
+
+export function base64_decode (this: FilterImpl, value: string): string {
+  const str = stringify(value)
+  this.context.memoryLimit.use(str.length)
+  return base64Decode(str)
+}

src/filters/index.ts

@@ -4,6 +4,7 @@ import * as urlFilters from './url'
 import * as arrayFilters from './array'
 import * as dateFilters from './date'
 import * as stringFilters from './string'
+import * as base64Filters from './base64'
 import misc from './misc'
 import { FilterImplOptions } from '../template'
 
@@ -14,5 +15,6 @@ export const filters: Record<string, FilterImplOptions> = {
   ...arrayFilters,
   ...dateFilters,
   ...stringFilters,
+  ...base64Filters,
   ...misc
 }