From a2304ec7ef01992d8620fef2bcc2efcead6d1bf6 Mon Sep 17 00:00:00 2001
From: flywind <xzsflywind@gmail.com>
Date: Tue, 17 Nov 2020 18:08:39 +0800
Subject: [PATCH 1/3] add simple writeStackTrace for JS backend

---
 lib/system.nim       | 2 +-
 lib/system/jssys.nim | 5 +++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/lib/system.nim b/lib/system.nim
index e41dfe1ca9f31..ab9140c13768b 100644
--- a/lib/system.nim
+++ b/lib/system.nim
@@ -1762,7 +1762,7 @@ when notJSnotNims and defined(nimSeqsV2):
 
 {.pop.}
 
-when notJSnotNims:
+when not defined(nimscript):
   proc writeStackTrace*() {.tags: [], gcsafe, raises: [].}
     ## Writes the current stack trace to ``stderr``. This is only works
     ## for debug builds. Since it's usually used for debugging, this
diff --git a/lib/system/jssys.nim b/lib/system/jssys.nim
index df05a9a62830c..d0be35dd097a5 100644
--- a/lib/system/jssys.nim
+++ b/lib/system/jssys.nim
@@ -105,6 +105,11 @@ proc rawWriteStackTrace(): string =
   else:
     result = "No stack traceback available\n"
 
+proc writeStackTrace() =
+  var trace = rawWriteStackTrace()
+  trace.setLen(trace.len - 1)
+  echo trace
+
 proc getStackTrace*(): string = rawWriteStackTrace()
 proc getStackTrace*(e: ref Exception): string = e.trace
 

From 30c6acabecbdc9f49ca3a9ff77793c73f6e52738 Mon Sep 17 00:00:00 2001
From: flywind <xzsflywind@gmail.com>
Date: Tue, 17 Nov 2020 21:09:40 +0800
Subject: [PATCH 2/3] add testcase for writeStackTrace

---
 tests/js/twritestacktrace.nim | 12 ++++++++++++
 1 file changed, 12 insertions(+)
 create mode 100644 tests/js/twritestacktrace.nim

diff --git a/tests/js/twritestacktrace.nim b/tests/js/twritestacktrace.nim
new file mode 100644
index 0000000000000..2fe2b1987a7e5
--- /dev/null
+++ b/tests/js/twritestacktrace.nim
@@ -0,0 +1,12 @@
+discard """
+  cmd: "nim js --panics:on $file"
+  output: '''Traceback (most recent call last)
+twritestacktrace.nim(12) at module twritestacktrace
+twritestacktrace.nim(10) at twritestacktrace.hello
+'''
+"""
+
+proc hello() =
+  writeStackTrace()
+
+hello()

From fb2f2ffd467959d19460ef4fd969a97207adbc72 Mon Sep 17 00:00:00 2001
From: flywind <xzsflywind@gmail.com>
Date: Tue, 17 Nov 2020 21:10:30 +0800
Subject: [PATCH 3/3] changelog

---
 changelog.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/changelog.md b/changelog.md
index d28edd34cded1..c5d65b50e6e2d 100644
--- a/changelog.md
+++ b/changelog.md
@@ -19,6 +19,8 @@
 
 - Added std/enumutils module containing `genEnumCaseStmt` macro that generates case statement to parse string to enum.
 
+- `writeStackTrace` is available in JS backend now.
+
 ## Language changes