simplify

Author: Rich-Harris

src/parse.js

@@ -14,23 +14,28 @@ import {
 export function parse(serialized) {
 	const parsed = JSON.parse(serialized);
 
-	if (typeof parsed === 'number') {
-		const constant = hydrateConstant(parsed);
-		if (constant === NOT_A_CONSTANT) throw new SyntaxError(`Unexpected number ${parsed}`);
-		return constant;
-	}
+	if (typeof parsed === 'number') return hydrate(parsed, true);
 
-	if (!Array.isArray(parsed)) throw new SyntaxError(`Expected array, got ${parsed === null ? 'null' : typeof parsed}`);
+	if (!Array.isArray(parsed)) {
+		throw new SyntaxError(
+			`Expected array, got ${parsed === null ? 'null' : typeof parsed}`
+		);
+	}
 
 	const values = /** @type {any[]} */ (parsed);
 	if (values.length === 0) throw new SyntaxError(`Unexpected empty array`);
 
 	const hydrated = Array(values.length);
 
 	/** @param {number} index */
-	function hydrate(index) {
-		const constant = hydrateConstant(index);
-		if (constant !== NOT_A_CONSTANT) return constant;
+	function hydrate(index, standalone = false) {
+		if (index === UNDEFINED) return undefined;
+		if (index === NAN) return NaN;
+		if (index === POSITIVE_INFINITY) return Infinity;
+		if (index === NEGATIVE_INFINITY) return -Infinity;
+		if (index === NEGATIVE_ZERO) return -0;
+
+		if (standalone) throw new SyntaxError(`Unexpected number ${index}`);
 
 		if (index in hydrated) return hydrated[index];
 
@@ -110,15 +115,3 @@ export function parse(serialized) {
 
 	return hydrate(0);
 }
-
-const NOT_A_CONSTANT = Symbol('not a constant');
-
-/** @param {number} constant */
-function hydrateConstant(constant) {
-	if (constant === UNDEFINED) return undefined;
-	if (constant === NAN) return NaN;
-	if (constant === POSITIVE_INFINITY) return Infinity;
-	if (constant === NEGATIVE_INFINITY) return -Infinity;
-	if (constant === NEGATIVE_ZERO) return -0;
-	return NOT_A_CONSTANT;
-}