Remove nested JSON.stringify from props serialization (#7995)

.changeset/great-icons-turn.md

@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fix quadratic quote escaping in nested data in island props

packages/astro/src/runtime/server/astro-island.ts

@@ -18,25 +18,32 @@ declare const Astro: {
 	}
 
 	const propTypes: PropTypeSelector = {
-		0: (value) => value,
+		0: (value) => reviveObject(value),
-		1: (value) => JSON.parse(value, reviver),
+		1: (value) => reviveArray(value),
 		2: (value) => new RegExp(value),
 		3: (value) => new Date(value),
-		4: (value) => new Map(JSON.parse(value, reviver)),
+		4: (value) => new Map(reviveArray(value)),
-		5: (value) => new Set(JSON.parse(value, reviver)),
+		5: (value) => new Set(reviveArray(value)),
 		6: (value) => BigInt(value),
 		7: (value) => new URL(value),
-		8: (value) => new Uint8Array(JSON.parse(value)),
+		8: (value) => new Uint8Array(value),
-		9: (value) => new Uint16Array(JSON.parse(value)),
+		9: (value) => new Uint16Array(value),
-		10: (value) => new Uint32Array(JSON.parse(value)),
+		10: (value) => new Uint32Array(value),
 	};
 
-	const reviver = (propKey: string, raw: string): any => {
+	// Not using JSON.parse reviver because it's bottom-up but we want top-down
-		if (propKey === '' || !Array.isArray(raw)) return raw;
+	const reviveTuple = (raw: any): any => {
 		const [type, value] = raw;
 		return type in propTypes ? propTypes[type](value) : undefined;
 	};
 
+	const reviveArray = (raw: any): any => (raw as Array<any>).map(reviveTuple);
+
+	const reviveObject = (raw: any): any => {
+		if (typeof raw !== 'object' || raw === null) return raw;
+		return Object.fromEntries(Object.entries(raw).map(([key, value]) => [key, reviveTuple(value)]));
+	};
+
 	if (!customElements.get('astro-island')) {
 		customElements.define(
 			'astro-island',
@@ -132,7 +139,7 @@ declare const Astro: {
 
 					try {
 						props = this.hasAttribute('props')
-							? JSON.parse(this.getAttribute('props')!, reviver)
+							? reviveObject(JSON.parse(this.getAttribute('props')!))
 							: {};
 					} catch (e) {
 						let componentName: string = this.getAttribute('component-url') || '<unknown>';

packages/astro/src/runtime/server/serialize.ts

@@ -4,7 +4,7 @@ type ValueOf<T> = T[keyof T];
 
 const PROP_TYPE = {
 	Value: 0,
-	JSON: 1,
+	JSON: 1, // Actually means Array
 	RegExp: 2,
 	Date: 3,
 	Map: 4,
@@ -68,16 +68,10 @@ function convertToSerializedForm(
 			return [PROP_TYPE.RegExp, (value as RegExp).source];
 		}
 		case '[object Map]': {
-			return [
+			return [PROP_TYPE.Map, serializeArray(Array.from(value as Map<any, any>), metadata, parents)];
-				PROP_TYPE.Map,
-				JSON.stringify(serializeArray(Array.from(value as Map<any, any>), metadata, parents)),
-			];
 		}
 		case '[object Set]': {
-			return [
+			return [PROP_TYPE.Set, serializeArray(Array.from(value as Set<any>), metadata, parents)];
-				PROP_TYPE.Set,
-				JSON.stringify(serializeArray(Array.from(value as Set<any>), metadata, parents)),
-			];
 		}
 		case '[object BigInt]': {
 			return [PROP_TYPE.BigInt, (value as bigint).toString()];
@@ -86,16 +80,16 @@ function convertToSerializedForm(
 			return [PROP_TYPE.URL, (value as URL).toString()];
 		}
 		case '[object Array]': {
-			return [PROP_TYPE.JSON, JSON.stringify(serializeArray(value, metadata, parents))];
+			return [PROP_TYPE.JSON, serializeArray(value, metadata, parents)];
 		}
 		case '[object Uint8Array]': {
-			return [PROP_TYPE.Uint8Array, JSON.stringify(Array.from(value as Uint8Array))];
+			return [PROP_TYPE.Uint8Array, Array.from(value as Uint8Array)];
 		}
 		case '[object Uint16Array]': {
-			return [PROP_TYPE.Uint16Array, JSON.stringify(Array.from(value as Uint16Array))];
+			return [PROP_TYPE.Uint16Array, Array.from(value as Uint16Array)];
 		}
 		case '[object Uint32Array]': {
-			return [PROP_TYPE.Uint32Array, JSON.stringify(Array.from(value as Uint32Array))];
+			return [PROP_TYPE.Uint32Array, Array.from(value as Uint32Array)];
 		}
 		default: {
 			if (value !== null && typeof value === 'object') {

packages/astro/test/serialize.test.js

@@ -34,7 +34,13 @@ describe('serialize', () => {
 	});
 	it('serializes an array', () => {
 		const input = { a: [0] };
-		const output = `{"a":[1,"[[0,0]]"]}`;
+		const output = `{"a":[1,[[0,0]]]}`;
+		expect(serializeProps(input)).to.equal(output);
+	});
+	it('can serialize deeply nested data without quadratic quote escaping', () => {
+		const input = { a: [{ b: [{ c: [{ d: [{ e: [{ f: [{ g: ['leaf'] }] }] }] }] }] }] };
+		const output =
+			'{"a":[1,[[0,{"b":[1,[[0,{"c":[1,[[0,{"d":[1,[[0,{"e":[1,[[0,{"f":[1,[[0,{"g":[1,[[0,"leaf"]]]}]]]}]]]}]]]}]]]}]]]}]]]}';
 		expect(serializeProps(input)).to.equal(output);
 	});
 	it('serializes a regular expression', () => {
@@ -49,12 +55,12 @@ describe('serialize', () => {
 	});
 	it('serializes a Map', () => {
 		const input = { a: new Map([[0, 1]]) };
-		const output = `{"a":[4,"[[1,\\"[[0,0],[0,1]]\\"]]"]}`;
+		const output = `{"a":[4,[[1,[[0,0],[0,1]]]]]}`;
 		expect(serializeProps(input)).to.equal(output);
 	});
 	it('serializes a Set', () => {
 		const input = { a: new Set([0, 1, 2, 3]) };
-		const output = `{"a":[5,"[[0,0],[0,1],[0,2],[0,3]]"]}`;
+		const output = `{"a":[5,[[0,0],[0,1],[0,2],[0,3]]]}`;
 		expect(serializeProps(input)).to.equal(output);
 	});
 	it('serializes a BigInt', () => {
@@ -69,17 +75,17 @@ describe('serialize', () => {
 	});
 	it('serializes a Uint8Array', () => {
 		const input = { a: new Uint8Array([1, 2, 3]) };
-		const output = `{"a":[8,"[1,2,3]"]}`;
+		const output = `{"a":[8,[1,2,3]]}`;
 		expect(serializeProps(input)).to.equal(output);
 	});
 	it('serializes a Uint16Array', () => {
 		const input = { a: new Uint16Array([1, 2, 3]) };
-		const output = `{"a":[9,"[1,2,3]"]}`;
+		const output = `{"a":[9,[1,2,3]]}`;
 		expect(serializeProps(input)).to.equal(output);
 	});
 	it('serializes a Uint32Array', () => {
 		const input = { a: new Uint32Array([1, 2, 3]) };
-		const output = `{"a":[10,"[1,2,3]"]}`;
+		const output = `{"a":[10,[1,2,3]]}`;
 		expect(serializeProps(input)).to.equal(output);
 	});
 	it('cannot serialize a cyclic reference', () => {