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Last active Dec 18, 2015
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Backporting the TypeScript filter to webassets 0.8 for use with tsc 0.9
"""This is an alternate typescript handler from future webassets as there
is a bug in the 0.8 version with recent tsc
import os
import subprocess
import tempfile
from io import open # Give 2 and 3 use same newline behaviour.
from webassets.filter import Filter, register_filter
from webassets.exceptions import FilterError
__all__ = ('TypeScriptAlt',)
class TypeScriptAlt(Filter):
"""Compile `TypeScript <>`_ to JavaScript.
TypeScript is an external tool written for NodeJS.
This filter assumes that the ``tsc`` executable is in the path. Otherwise, you
may define the ``TYPESCRIPT_BIN`` setting.
name = 'typescriptalt'
max_debug_level = None
options = {
'binary': 'TYPESCRIPT_BIN',
def output(self, _in, out, **kw):
# The typescript compiler cannot read a file which does not have
# the .ts extension. The output file needs to have an extension,
# or the compiler will want to create a directory in its place.
input_filename = tempfile.mktemp() + ".ts"
output_filename = tempfile.mktemp() + ".js"
with open(input_filename, 'wb') as f:
args = [self.binary or 'tsc', '--out', output_filename, input_filename
proc = subprocess.Popen(
stdout, stderr = proc.communicate()
if proc.returncode != 0:
raise FilterError("typescript: subprocess had error: stderr=%s," % stderr +
"stdout=%s, returncode=%s" % (stdout, proc.returncode))
with open(output_filename, 'r') as f:
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