From 2cfe5e0745cf33ed5698378dd16e01ce542f05e5 Mon Sep 17 00:00:00 2001
From: flywind <43030857+xflywind@users.noreply.github.com>
Date: Fri, 30 Oct 2020 22:34:07 +0800
Subject: [PATCH] [closes #11625 and closes #2488]add global and threadvar(with
 `--threads:off` mode ) pragmas supports for JS backend (#15772)

* add global pragma support for js backend

* globalThis

* add support for threadvar

* more tests

* Update compiler/jsgen.nim

Co-authored-by: Andreas Rumpf <rumpf_a@web.de>
---
 compiler/jsgen.nim   |  7 ++++++-
 tests/js/tglobal.nim | 30 ++++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+), 1 deletion(-)
 create mode 100644 tests/js/tglobal.nim

diff --git a/compiler/jsgen.nim b/compiler/jsgen.nim
index 8b91ada8a0..766e6a80d4 100644
--- a/compiler/jsgen.nim
+++ b/compiler/jsgen.nim
@@ -1736,6 +1736,7 @@ proc genVarInit(p: PProc, v: PSym, n: PNode) =
     varCode: string
     varName = mangleName(p.module, v)
     useReloadingGuard = sfGlobal in v.flags and p.config.hcrOn
+    useGlobalPragmas = sfGlobal in v.flags and ({sfPure, sfThread} * v.flags != {})
 
   if v.constraint.isNil:
     if useReloadingGuard:
@@ -1743,6 +1744,10 @@ proc genVarInit(p: PProc, v: PSym, n: PNode) =
       lineF(p, "if ($1 === undefined) {$n", varName)
       varCode = $varName
       inc p.extraIndent
+    elif useGlobalPragmas:
+      lineF(p, "if (globalThis.$1 === undefined) {$n", varName)
+      varCode = $varName
+      inc p.extraIndent
     else:
       varCode = "var $2"
   else:
@@ -1795,7 +1800,7 @@ proc genVarInit(p: PProc, v: PSym, n: PNode) =
     else:
       line(p, runtimeFormat(varCode & " = $3;$n", [returnType, v.loc.r, s]))
 
-  if useReloadingGuard:
+  if useReloadingGuard or useGlobalPragmas:
     dec p.extraIndent
     lineF(p, "}$n")
 
diff --git a/tests/js/tglobal.nim b/tests/js/tglobal.nim
new file mode 100644
index 0000000000..38f5eec34f
--- /dev/null
+++ b/tests/js/tglobal.nim
@@ -0,0 +1,30 @@
+block global:
+  proc getState(): int =
+    var state0 {.global.}: int
+    inc state0
+    result = state0
+
+  for i in 0 ..< 3:
+    doAssert getState() == i + 1
+
+  for i in 0 ..< 3:
+    once:
+      doAssert i == 0
+
+
+block threadvar:
+  proc getThreadState0(): int =
+    var state0 {.threadvar.}: int
+    inc state0
+    result = state0
+
+  for i in 0 ..< 3:
+    doAssert getThreadState0() == i + 1
+
+  proc getThreadState1(): int =
+    var state1 {.threadvar.}: int
+    inc state1
+    result = state1
+
+  for i in 0 ..< 3:
+    doAssert getThreadState1() == i + 1