Fix tracing -0

overlookmotel · Sep 9, 2023 · 14cc078 · 14cc078
1 parent 9e800a2
commit 14cc078
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Showing 2 changed files with 24 additions and 3 deletions.
diff --git a/lib/serialize/primitives.js b/lib/serialize/primitives.js
@@ -24,7 +24,7 @@ const {
 
 const bigIntToString = BigInt.prototype.toString;
 
-module.exports = {tracePrimitive};
+module.exports = {tracePrimitive, traceMinusZero};
 
 /**
  * Trace primitive value.
@@ -81,8 +81,7 @@ function traceBoolean(val, record) {
  * @returns {number} - Type ID
  */
 function traceNumber(val, record) {
-	// `Object.is()` required to differentiate between 0 and -0
-	if (val < 0 || Object.is(val, -0)) {
+	if (val < 0) {
 		record.name = `minus${-val}`;
 		record.extra = {positive: this.traceDependency(-val, null, null, record)};
 		return NEGATIVE_TYPE;
@@ -93,6 +92,18 @@ function traceNumber(val, record) {
 	return NUMBER_TYPE;
 }
 
+/**
+ * Trace minus zero.
+ * @this {Object} Serializer
+ * @param {Object} record - Record
+ * @returns {number} - Type ID
+ */
+function traceMinusZero(record) {
+	record.name = 'minus0';
+	record.extra = {positive: this.traceDependency(0, null, null, record)};
+	return NEGATIVE_TYPE;
+}
+
 /**
  * Trace `BigInt`.
  * @this {Object} Serializer

diff --git a/lib/serialize/trace.js b/lib/serialize/trace.js
@@ -33,6 +33,7 @@ module.exports = {
 	 */
 	initTrace() {
 		this.traceStack = [];
+		this.minusZeroRecord = null;
 	},
 
 	/**
@@ -52,6 +53,15 @@ module.exports = {
 	},
 
 	traceValueInner(val, name) {
+		// Special case -0 because 0 and -0 are treated as equal as Map keys
+		if (Object.is(val, -0)) {
+			if (this.minusZeroRecord) return this.minusZeroRecord;
+			const record = createRecord(name);
+			record.type = this.traceMinusZero(record);
+			this.minusZeroRecord = record;
+			return record;
+		}
+
 		// Use existing record
 		const {records} = this;
 		let record = records.get(val);