feat: Deno.core.{encode,decode}; standalone UTF-8 encoding/decoding (#4349)

This commits add two new methods to "Deno.core" namespace: "encode" and "decode".

Those methods are bound in Rust to provide a) fast b) generally available of encoding and decoding UTF-8 strings. 

Both methods are now used in "cli/js/dispatch_json.ts".

1 files changed, 32 insertions, 0 deletions

diff --git a/cli/tests/core_encode_perf.js b/cli/tests/core_encode_perf.js
new file mode 100644
index 000000000..5cde81c7a
--- /dev/null
+++ b/cli/tests/core_encode_perf.js
@@ -0,0 +1,32 @@
+const mixed = "@Ā๐😀";
+
+function generateRandom(bytes) {
+  let result = "";
+  let i = 0;
+  while (i < bytes) {
+    const toAdd = Math.floor(Math.random() * Math.min(4, bytes - i));
+    switch (toAdd) {
+      case 0:
+        result += mixed[0];
+        i++;
+        break;
+      case 1:
+        result += mixed[1];
+        i++;
+        break;
+      case 2:
+        result += mixed[2];
+        i++;
+        break;
+      case 3:
+        result += mixed[3];
+        result += mixed[4];
+        i += 2;
+        break;
+    }
+  }
+  return result;
+}
+
+const randomData = generateRandom(1024);
+for (let i = 0; i < 10_000; i++) Deno.core.encode(randomData);