feat: add array index support in nested multipart form parsing

src/adapter/web-standard/index.ts

@@ -52,16 +52,35 @@ export const WebStandardAdapter: ElysiaAdapter = {
 					`if(c.body[key]) continue\n` +
 					`const value=form.getAll(key)\n` +
 					`const finalValue=value.length===1?value[0]:value\n` +
-					`if(key.includes('.')){` +
+					`if(key.includes('.')||key.includes('[')){` +
 					`const keys=key.split('.')\n` +
 					`const lastKey=keys.pop()\n` +
 					`let current=c.body\n` +
 					`for(const k of keys){` +
+					`const arrayMatch=k.match(/^(.+)\\[(\\d+)\\]$/)\n` +
+					`if(arrayMatch){` +
+					`const arrayKey=arrayMatch[1]\n` +
+					`const index=parseInt(arrayMatch[2],10)\n` +
+					`if(!(arrayKey in current))current[arrayKey]=[]\n` +
+					`if(!Array.isArray(current[arrayKey]))current[arrayKey]=[]\n` +
+					`if(!current[arrayKey][index])current[arrayKey][index]={}\n` +
+					`current=current[arrayKey][index]` +
+					`}else{` +
 					`if(!(k in current)||typeof current[k]!=='object'||current[k]===null)` +
 					`current[k]={}\n` +
 					`current=current[k]` +
+					`}` +
 					`}\n` +
+					`const lastArrayMatch=lastKey.match(/^(.+)\\[(\\d+)\\]$/)\n` +
+					`if(lastArrayMatch){` +
+					`const arrayKey=lastArrayMatch[1]\n` +
+					`const index=parseInt(lastArrayMatch[2],10)\n` +
+					`if(!(arrayKey in current))current[arrayKey]=[]\n` +
+					`if(!Array.isArray(current[arrayKey]))current[arrayKey]=[]\n` +
+					`current[arrayKey][index]=finalValue` +
+					`}else{` +
 					`current[lastKey]=finalValue` +
+					`}` +
 					`}else c.body[key]=finalValue` +
 					`}`
 				)

src/dynamic-handle.ts

@@ -29,17 +29,50 @@ const setNestedValue = (
 	path: string,
 	value: any
 ) => {
+	// Split by dots, but preserve array indices
 	const keys = path.split('.')
 	const lastKey = keys.pop()!
 
 	let current = obj
 	for (const key of keys) {
-		if (!(key in current) || typeof current[key] !== 'object' || current[key] === null)
-			current[key] = {}
-		current = current[key]
+		// Check if key has array index notation: key[0], key[1], etc.
+		const arrayMatch = key.match(/^(.+)\[(\d+)\]$/)
+
+		if (arrayMatch) {
+			const [, arrayKey, indexStr] = arrayMatch
+			const index = parseInt(indexStr, 10)
+
+			// Initialize array if needed
+			if (!(arrayKey in current)) current[arrayKey] = []
+
+			// Ensure it's an array
+			if (!Array.isArray(current[arrayKey])) current[arrayKey] = []
+
+			// Initialize object at index if needed
+			if (!current[arrayKey][index]) current[arrayKey][index] = {}
+
+			current = current[arrayKey][index]
+		} else {
+			// Regular object property
+			if (!(key in current) || typeof current[key] !== 'object' || current[key] === null)
+				current[key] = {}
+			current = current[key]
+		}
 	}
 
-	current[lastKey] = value
+	// Handle array index in last key
+	const arrayMatch = lastKey.match(/^(.+)\[(\d+)\]$/)
+	if (arrayMatch) {
+		const [, arrayKey, indexStr] = arrayMatch
+		const index = parseInt(indexStr, 10)
+
+		if (!(arrayKey in current)) current[arrayKey] = []
+		if (!Array.isArray(current[arrayKey])) current[arrayKey] = []
+
+		current[arrayKey][index] = value
+	} else {
+		current[lastKey] = value
+	}
 }
 
 const injectDefaultValues = (
@@ -159,7 +192,7 @@ export const createDynamicHandler = (app: AnyElysia) => {
 								const value = form.getAll(key)
 								const finalValue = value.length === 1 ? value[0] : value
 
-								if (key.includes('.'))
+								if (key.includes('.') || key.includes('['))
 									setNestedValue(body, key, finalValue)
 								else body[key] = finalValue
 							}
@@ -220,7 +253,7 @@ export const createDynamicHandler = (app: AnyElysia) => {
 												const value = form.getAll(key)
 												const finalValue = value.length === 1 ? value[0] : value
 
-												if (key.includes('.'))
+												if (key.includes('.') || key.includes('['))
 													setNestedValue(body, key, finalValue)
 												else body[key] = finalValue
 											}
@@ -290,7 +323,7 @@ export const createDynamicHandler = (app: AnyElysia) => {
 										const value = form.getAll(key)
 										const finalValue = value.length === 1 ? value[0] : value
 
-										if (key.includes('.'))
+										if (key.includes('.') || key.includes('['))
 											setNestedValue(body, key, finalValue)
 										else body[key] = finalValue
 									}

test/validator/body.test.ts

@@ -1298,4 +1298,70 @@ describe('Body Validator', () => {
 		expect(result.nestedName).toBe('Jane')
 		expect(result.nestedFileSize).toBeGreaterThan(0)
 	})
+
+	it('handle complex nested array with files', async () => {
+		const app = new Elysia().post(
+			'/',
+			({ body }) => ({
+				productName: body.name,
+				createFilesCount: body.images.create.length,
+				updateCount: body.images.update.length,
+				images: {
+					create: body.images.create.map((f) => f.size),
+					update: body.images.update.map((f) => ({
+						id: f.id,
+						altText: f.altText,
+						imgSize: f.img.size
+					}))
+				}
+			}),
+			{
+				body: t.Object({
+					name: t.String(),
+					images: t.Object({
+						create: t.Files(),
+						update: t.Array(
+							t.Object({
+								id: t.String(),
+								img: t.File(),
+								altText: t.String()
+							})
+						)
+					})
+				})
+			}
+		)
+
+		const formData = new FormData()
+		formData.append('name', 'My Product')
+		formData.append('images.create[0]', Bun.file('test/images/millenium.jpg'))
+		formData.append('images.create[1]', Bun.file('test/images/kozeki-ui.webp'))
+		formData.append('images.update[0].id', '1')
+		formData.append('images.update[0].img', Bun.file('test/images/midori.png'))
+		formData.append('images.update[0].altText', 'First image')
+		formData.append('images.update[1].id', '2')
+		formData.append('images.update[1].img', Bun.file('test/images/aris-yuzu.jpg'))
+		formData.append('images.update[1].altText', 'Second image')
+
+		const response = await app.handle(
+			new Request('http://localhost/', {
+				method: 'POST',
+				body: formData
+			})
+		)
+
+		const result = await response.json()
+		expect(response.status).toBe(200)
+		expect(result.productName).toBe('My Product')
+		expect(result.createFilesCount).toBe(2)
+		expect(result.updateCount).toBe(2)
+		expect(result.images.create[0]).toBeGreaterThan(0)
+		expect(result.images.create[1]).toBeGreaterThan(0)
+		expect(result.images.update[0].id).toBe('1')
+		expect(result.images.update[0].altText).toBe('First image')
+		expect(result.images.update[0].imgSize).toBeGreaterThan(0)
+		expect(result.images.update[1].id).toBe('2')
+		expect(result.images.update[1].altText).toBe('Second image')
+		expect(result.images.update[1].imgSize).toBeGreaterThan(0)
+	})
 })