[TS/JS] Entry point per namespace and reworked 1.x compatible single file build (#7510)

* [TS/JS] Entry point per namespace

* Fix handling of outputpath and array_test

* Attempt to fix generate_code

* Fix cwd for ts in generate_code

* Attempt to fixup bazel and some docs

* Add --ts-flat-files to bazel build to get bundle

* Move to DEFAULT_FLATC_TS_ARGS

* Attempt to add esbuild

* Attempt to use npm instead

* Remove futile attempt to add esbuild

* Attempt to as bazel esbuild

* Shuffle

* Upgrade bazel deps

* Revert failed attempts to get bazel working

* Ignore flatc tests for now

* Add esbuild dependency

* `package.json` Include esbuild

* `WORKSPACE` Add fetching esbuild binary

* Update WORKSPACE

* Unfreeze Lockfile

* Update WORKSPACE

* Update BUILD.bazel

* Rework to suggest instead of running external bundler

* Add esbuild generation to test script

* Prelim bundle test

* Run test JavaScriptTest from flatbuffers 1.x

* Deps upgrade

* Clang format fix

* Revert bazel changes

* Fix newline

* Generate with type declarations

* Handle "empty" root namespace

* Adjust tests for typescript_keywords.ts

* Separate test procedure for old node resolution module output

* Fix rel path for root level re-exports

* Bazel support for esbuild-based flatc

Unfortunately, we lose typing information because the new esbuild method
of generating single files does not generate type information.

The method used here is a bit hack-ish because it relies on parsing the
console output of flatc to figure out what to do.

* Try to fix bazel build for when node isn't present on host

* Auto formatting fixes

* Fix missing generated code

Co-authored-by: Derek Bailey <derekbailey@google.com>
Co-authored-by: James Kuszmaul <jabukuszmaul+collab@gmail.com>

ts/BUILD.bazel

@@ -8,7 +8,7 @@ ts_project(
         "byte-buffer.ts",
         "constants.ts",
         "encoding.ts",
-        "index.ts",
+        "flatbuffers.ts",
         "types.ts",
         "utils.ts",
     ],
@@ -37,3 +37,21 @@ js_library(
     visibility = ["//visibility:public"],
     deps = [":flatbuffers_ts"],
 )
+
+sh_binary(
+    name = "compile_flat_file",
+    srcs = ["compile_flat_file.sh"],
+    data = [
+        "@com_github_google_flatbuffers//:flatc",
+        "@nodejs_linux_amd64//:node_bin",
+        "@npm//esbuild/bin:esbuild",
+    ],
+    # We just depend directly on the linux amd64 nodejs binary, so only support
+    # running this script on amd64 for now.
+    target_compatible_with = [
+        "@platforms//cpu:x86_64",
+        "@platforms//os:linux",
+    ],
+    visibility = ["//visibility:public"],
+    deps = ["@bazel_tools//tools/bash/runfiles"],
+)