add parser benchmarks

Author: diegommm

parser/bench_test.go

@@ -0,0 +1,20 @@
+package parser
+
+import "testing"
+
+func BenchmarkParser(b *testing.B) {
+	const source = `
+		/*
+			Showing worst case scenario
+		*/
+		let value = trim("contains escapes \n\"\\ \U0001F600 and non ASCII ñ"); // inline comment
+		len(value) == 0x2A
+		// let's introduce an error too
+		whatever
+	`
+	b.ReportAllocs()
+	p := new(Parser)
+	for i := 0; i < b.N; i++ {
+		p.Parse(source, nil)
+	}
+}