fix: handle Union with objects in query array params

src/parse-query.ts

@@ -91,9 +91,11 @@ export function parseQueryFromURL(
 
 		if (array && array?.[finalKey]) {
 			if (finalValue.charCodeAt(0) === 91) {
-				if (object && object?.[finalKey])
+				try {
 					finalValue = JSON.parse(finalValue) as any
-				else finalValue = finalValue.slice(1, -1).split(',') as any
+				} catch {
+					finalValue = finalValue.slice(1, -1).split(',') as any
+				}
 
 				if (currentValue === undefined) result[finalKey] = finalValue
 				else if (Array.isArray(currentValue))
@@ -103,10 +105,10 @@ export function parseQueryFromURL(
 					result[finalKey].unshift(currentValue)
 				}
 			} else {
+				// join multi-param values as comma-separated so ArrayQuery
+				// Decode handles them uniformly (same as comma format)
 				if (currentValue === undefined) result[finalKey] = finalValue
-				else if (Array.isArray(currentValue))
-					currentValue.push(finalValue)
-				else result[finalKey] = [currentValue, finalValue]
+				else result[finalKey] = currentValue + ',' + finalValue
 			}
 		} else {
 			result[finalKey] = finalValue

src/type-system/index.ts

@@ -425,12 +425,56 @@ export const ElysiaType = {
 		const schema = t.Array(children, options)
 		const compiler = compile(schema)
 
+		const tryParseItem = (v: string) => {
+			const c = v.charCodeAt(0)
+			if (c === 123 || c === 91) {
+				try { return JSON.parse(v) } catch {}
+			}
+			return v
+		}
+
+		// split by commas but respect {} [] and quoted strings
+		const splitTopLevel = (value: string) => {
+			const parts: string[] = []
+			let depth = 0
+			let inStr = 0 // 0=none, 34=", 39='
+			let start = 0
+
+			for (let i = 0; i < value.length; i++) {
+				const ch = value.charCodeAt(i)
+
+				if (inStr) {
+					if (ch === inStr && value.charCodeAt(i - 1) !== 92)
+						inStr = 0
+					continue
+				}
+
+				if (ch === 34 || ch === 39) { inStr = ch; continue }
+				if (ch === 123 || ch === 91) { depth++; continue }
+				if (ch === 125 || ch === 93) { depth--; continue }
+
+				if (ch === 44 && depth === 0) {
+					parts.push(value.slice(start, i))
+					start = i + 1
+				}
+			}
+
+			parts.push(value.slice(start))
+			return parts
+		}
+
 		const decode = (value: string) => {
-			// has , (as used in nuqs)
-			if (value.indexOf(',') !== -1)
-				return compiler.Decode(value.split(','))
+			if (value.indexOf(',') !== -1) {
+				try {
+					return compiler.Decode(JSON.parse(`[${value}]`))
+				} catch {
+					return compiler.Decode(
+						splitTopLevel(value).map(tryParseItem)
+					)
+				}
+			}
 
-			return compiler.Decode([value])
+			return compiler.Decode([tryParseItem(value)])
 		}
 
 		return t