par-core is used at run time in 50 crates (of which 4 optionally). It is a direct run-time dependency in 15 crates. It's used only as a dev dependency in 5 crates.

Depender (with downloads and own rev deps) par-core version
169K 61 swc_ecma_utils ^1.0.3
166K 52 swc_ecma_transforms_base ^1.0.3
75K 8 swc_ecma_transforms_optimization ^1.0.3
69K 18 swc_ecma_minifier ^1.0.3
25K 3 par-iter ^1.0.0
20K 12 swc_ecma_transforms_compat ^1.0.3
16K 15 swc_ecma_transforms ^1.0.3
14K 22 swc ^1.0.3
14K 3 swc_ecma_lints ^1.0.3
28K 84 swc_core optional ^1.0.3
1.5K swc_cli ^1.0.0
900 1 swc_cli_impl ^1.0.3
180 dbg-swc ^1.0.3
51K 10 swc_bundler dev ^1.0.3
360 12 swc_ecmascript dev ^1.0.3