Moar speed in arrays (#359)

* Improve rendering speed of arrays over JSON.stringify()

This restore some perf that got lost along the way, moving from 4k
ops/sec to 7k ops/sec in our array bench.

* Bench updates

Author: mcollina

README.md

@@ -12,22 +12,25 @@ __fast-json-stringify__ is significantly faster than `JSON.stringify()` for smal
 ##### Benchmarks
 
 - Machine: `EX41S-SSD, Intel Core i7, 4Ghz, 64GB RAM, 4C/8T, SSD`.
-- Node.js `v12.16.2`
+- Node.js `v16.9.1`
 
 ```
-FJS creation x 59,805 ops/sec ±0.23% (91 runs sampled)
+FJS creation x 6,040 ops/sec ±1.17% (91 runs sampled)
 
-JSON.stringify array x 5,330 ops/sec ±0.54% (97 runs sampled)
-fast-json-stringify array x 6,995 ops/sec ±0.24% (94 runs sampled)
+JSON.stringify array x 5,519 ops/sec ±0.08% (99 runs sampled)
+fast-json-stringify array x 7,143 ops/sec ±0.14% (97 runs sampled)
 
-JSON.stringify long string x 15,108 ops/sec ±0.13% (100 runs sampled)
-fast-json-stringify long string x 15,089 ops/sec ±0.15% (98 runs sampled)
+JSON.stringify long string x 16,438 ops/sec ±0.32% (98 runs sampled)
+fast-json-stringify long string x 16,457 ops/sec ±0.09% (97 runs sampled)
 
-JSON.stringify short string x 13,214,696 ops/sec ±0.19% (97 runs sampled)
-fast-json-stringify short string x 33,378,500 ops/sec ±0.27% (95 runs sampled)
+JSON.stringify short string x 12,061,258 ops/sec ±0.32% (97 runs sampled)
+fast-json-stringify short string x 35,531,071 ops/sec ±0.17% (94 runs sampled)
 
-JSON.stringify obj x 3,172,653 ops/sec ±0.15% (98 runs sampled)
-fast-json-stringify obj x 13,537,123 ops/sec ±0.19% (95 runs sampled)
+JSON.stringify obj x 3,079,746 ops/sec ±0.09% (95 runs sampled)
+fast-json-stringify obj x 7,721,569 ops/sec ±0.12% (98 runs sampled)
+
+JSON stringify date x 1,149,786 ops/sec ±0.10% (99 runs sampled)
+fast-json-stringify date format x 1,674,498 ops/sec ±0.12% (99 runs sampled)
 ```
 
 #### Table of contents:

index.js

@@ -1017,17 +1017,15 @@ function buildArray (location, code, name, key = null) {
 
   code += `
     var l = obj.length
-    var jsonOutput=''
-    var jsonLastChar
+    var jsonOutput= ''
     for (var i = 0; i < l; i++) {
       var json = ''
-
-      if (jsonLastChar && jsonLastChar.length && jsonLastChar !== ',') {
-        json += ','
-      }
       ${result.code}
-      jsonLastChar = json.slice(-1)
       jsonOutput += json
+
+      if (json.length > 0 && i < l - 1) {
+        jsonOutput += ','
+      }
     }
     return \`[\${jsonOutput}]\`
   }