1270 releases (67 stable)
new 23.0.5 | Jun 30, 2025 |
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22.0.0 | Jun 18, 2025 |
21.0.4 | Jun 14, 2025 |
20.0.5 | Jun 4, 2025 |
0.16.1 | Jul 31, 2021 |
#1252 in Web programming
68,676 downloads per month
Used in 84 crates
(21 directly)
8.5MB
222K
SLoC
Minifier
EcmaScript minifier for the SWC project. This is basically a port of terser.
Note
Currently name mangler is very simple. To focus on creating a MVP, I (kdy1) will use simple logic for name mangler and implement the content-aware name mangler after publishing first non-beta version.
Debugging tips
If the output contains variables named e
, t
, n
it typically means the original library is published in a minified form and the input contains eval
.
The current swc name mangler does not do anything if eval
is used.
Profiling the minifier
From mac os x, run
./scripts/instrument/all.sh path/to/input/dir
Contributing
Testing
Please prefer execution tests over unit tests. Execution tests are more useful because there's no chance of human error while reviewing.
Execution tests
You can add a test to ./tests/exec.rs
You can run ./scripts/exec.sh
from ./crates/swc_ecma_minifier
to run execution tests of SWC minifier. exec.sh
runs the cargo test with --features debug
, and it makes the cargo test print lots of debug logging. You can search for "change"
, and you can know the code responsible the optimization. The minifier has report_change!
macro, and it prints the location of the relevant code.
Fixture tests
You can add a test to ./tests/fixture
. You can select any directory, but please prefer to use the issues
directory. You can run ./scripts/test.sh
from ./crates/swc_ecma_minifier
to run fixture tests. You can run it like ./scripts/test.sh foo
to run test cases only with foo
in the file path. If you want to get location of change, you can do ./scripts/test.sh foo --features debug
.
Dependencies
~17–28MB
~435K SLoC