Compares the speed and package size of various ECMAScript parsers and code generators.
The new contender meriyah runs twice as fast as the old bard esprima. Babel produces an AST, which is not compatible with the other parsers.
Generating code with astring is faster than with escodegen.
git clone https://github.com/prantlf/ecmascript-parser-benchmark.git
cd ecmascript-parser-benchmark
pnpm i
npm start
❯ node perf/script && node perf/module && \
node perf/script --locations && node perf/module --locations
Parsing jquery.js as a script by...
esprima x 92.34 ops/sec ±0.82% (79 runs sampled)
acorn x 94.69 ops/sec ±0.61% (81 runs sampled)
babel x 45.87 ops/sec ±2.62% (61 runs sampled)
hermes x 23.77 ops/sec ±5.10% (44 runs sampled)
meriyah x 182 ops/sec ±0.83% (84 runs sampled)
kataw x 115 ops/sec ±1.63% (84 runs sampled)
seafox x 104 ops/sec ±1.95% (76 runs sampled)
cherow x 135 ops/sec ±2.11% (77 runs sampled)
escaya x 91.67 ops/sec ±1.76% (70 runs sampled)
tenko x 68.73 ops/sec ±1.37% (71 runs sampled)
Parsing collection-view.js as a module by...
esprima x 1,558 ops/sec ±0.73% (91 runs sampled)
acorn x 1,467 ops/sec ±0.58% (94 runs sampled)
babel x 1,228 ops/sec ±3.77% (88 runs sampled)
hermes x 460 ops/sec ±0.58% (93 runs sampled)
meriyah x 2,659 ops/sec ±2.09% (86 runs sampled)
kataw x 2,234 ops/sec ±1.03% (89 runs sampled)
seafox x 2,272 ops/sec ±3.51% (89 runs sampled)
cherow x 2,911 ops/sec ±1.04% (92 runs sampled)
escaya x 2,456 ops/sec ±2.24% (90 runs sampled)
tenko x 1,152 ops/sec ±1.10% (90 runs sampled)
tree-sitter x 325 ops/sec ±1.09% (86 runs sampled)
Parsing jquery.js as a script with locations by...
esprima x 75.89 ops/sec ±1.98% (66 runs sampled)
acorn x 55.51 ops/sec ±2.35% (59 runs sampled)
babel x 43.29 ops/sec ±3.45% (58 runs sampled)
hermes x 24.15 ops/sec ±4.71% (44 runs sampled)
meriyah x 91.36 ops/sec ±3.27% (67 runs sampled)
kataw x 86.75 ops/sec ±2.78% (65 runs sampled)
seafox x 79.40 ops/sec ±2.77% (69 runs sampled)
cherow x 85.76 ops/sec ±2.68% (64 runs sampled)
escaya x 81.44 ops/sec ±2.02% (70 runs sampled)
tenko x 55.39 ops/sec ±2.80% (59 runs sampled)
Parsing collection-view.js as a module with locations by...
esprima x 1,368 ops/sec ±1.39% (92 runs sampled)
acorn x 1,190 ops/sec ±0.95% (92 runs sampled)
babel x 1,151 ops/sec ±0.88% (91 runs sampled)
hermes x 426 ops/sec ±1.06% (87 runs sampled)
meriyah x 2,206 ops/sec ±0.74% (90 runs sampled)
kataw x 2,071 ops/sec ±1.26% (86 runs sampled)
seafox x 2,057 ops/sec ±0.85% (90 runs sampled)
cherow x 2,228 ops/sec ±0.84% (90 runs sampled)
escaya x 2,171 ops/sec ±1.11% (85 runs sampled)
tenko x 1,015 ops/sec ±1.09% (90 runs sampled)
tree-sitter x 309 ops/sec ±1.31% (87 runs sampled)
The hermes parser always creates an AST with source code locations. They cannot be disabled to gain more performance.
The tree-sitter parser always creates an AST with source code locations. They cannot be disabled to gain more performance. It makes no difference between a script and a module either.
The tree-sitter parser failed witn an invalid argument when parsing jquery.js.
❯ bun perf/script.js && bun perf/module.js && \
bun perf/script --locations && node perf/module --locations
Parsing jquery.js as a script by...
esprima x 60.09 ops/sec ±1.71% (63 runs sampled)
acorn x 68.57 ops/sec ±1.53% (71 runs sampled)
babel x 44.51 ops/sec ±1.68% (58 runs sampled)
hermes x 34.13 ops/sec ±1.99% (60 runs sampled)
meriyah x 166 ops/sec ±1.38% (77 runs sampled)
kataw x 108 ops/sec ±1.67% (72 runs sampled)
seafox x 123 ops/sec ±2.14% (73 runs sampled)
cherow x 126 ops/sec ±1.90% (72 runs sampled)
escaya x 105 ops/sec ±1.94% (69 runs sampled)
tenko x 56.54 ops/sec ±3.48% (60 runs sampled)
Parsing collection-view.js as a module by...
esprima x 1,034 ops/sec ±2.60% (89 runs sampled)
acorn x 1,102 ops/sec ±1.26% (92 runs sampled)
babel x 860 ops/sec ±3.69% (81 runs sampled)
hermes x 572 ops/sec ±5.01% (92 runs sampled)
meriyah x 2,681 ops/sec ±0.82% (92 runs sampled)
kataw x 2,267 ops/sec ±0.83% (93 runs sampled)
seafox x 2,353 ops/sec ±0.97% (91 runs sampled)
cherow x 2,142 ops/sec ±1.29% (85 runs sampled)
escaya x 2,117 ops/sec ±0.98% (91 runs sampled)
tenko x 988 ops/sec ±1.21% (88 runs sampled)
Parsing jquery.js as a script with locations by...
esprima x 59.12 ops/sec ±1.38% (62 runs sampled)
acorn x 62.63 ops/sec ±0.94% (66 runs sampled)
babel x 43.48 ops/sec ±1.76% (58 runs sampled)
hermes x 38.07 ops/sec ±1.76% (51 runs sampled)
meriyah x 138 ops/sec ±1.70% (79 runs sampled)
kataw x 119 ops/sec ±2.44% (77 runs sampled)
seafox x 117 ops/sec ±1.80% (75 runs sampled)
cherow x 113 ops/sec ±1.60% (74 runs sampled)
escaya x 100 ops/sec ±1.56% (74 runs sampled)
tenko x 60.35 ops/sec ±1.76% (63 runs sampled)
Parsing collection-view.js as a module with locations by...
esprima x 882 ops/sec ±4.56% (85 runs sampled)
acorn x 985 ops/sec ±0.79% (91 runs sampled)
babel x 861 ops/sec ±1.49% (87 runs sampled)
hermes x 530 ops/sec ±5.70% (89 runs sampled)
meriyah x 1,847 ops/sec ±1.86% (85 runs sampled)
kataw x 1,795 ops/sec ±1.02% (83 runs sampled)
seafox x 1,674 ops/sec ±0.89% (85 runs sampled)
cherow x 1,491 ops/sec ±2.34% (82 runs sampled)
escaya x 1,661 ops/sec ±1.53% (88 runs sampled)
tenko x 908 ops/sec ±1.68% (87 runs sampled)
The tree-sitter parser uses native libraries and node-gyp, which doesn't run in Bun.
❯ node perf/generator && node perf/generator --source-map
Generating code for an AST from jquery.js by...
escodegen x 104 ops/sec ±0.92% (76 runs sampled)
astring x 465 ops/sec ±0.84% (90 runs sampled)
babel x 61.33 ops/sec ±0.80% (64 runs sampled)
Generating code with source maps for an AST from jquery.js by...
escodegen x 4.67 ops/sec ±2.16% (16 runs sampled)
astring x 97.91 ops/sec ±2.25% (72 runs sampled)
babel x 34.96 ops/sec ±3.29% (61 runs sampled)
❯ bun perf/generator.js && bun perf/generator.js --source-map
Generating code for an AST from jquery.js by...
escodegen x 76.41 ops/sec ±2.72% (66 runs sampled)
astring x 483 ops/sec ±2.03% (78 runs sampled)
babel x 59.58 ops/sec ±0.89% (62 runs sampled)
Generating code with source maps for an AST from jquery.js by...
escodegen x 7.95 ops/sec ±1.87% (24 runs sampled)
astring x 158 ops/sec ±1.18% (79 runs sampled)
babel x 35.48 ops/sec ±1.20% (62 runs sampled)
❯ package-size esprima acorn @babel/parser hermes meriyah seafox kataw \
cherow @azariasb/escaya tenko tree-sitter tree-sitter-javascript
package size minified gzipped
esprima@4.0.1 278.47 KB 132.14 KB 28.59 KB
acorn@8.12.1 221.78 KB 113.71 KB 32.74 KB
@babel/parser@7.24.8 476.68 KB 282.87 KB 73.59 KB
hermes@0.4.4 308.87 KB 53.94 KB 17.98 KB
meriyah@4.3.0 128.94 KB 127.33 KB 40.25 KB
seafox@1.7.1 95 KB 93.41 KB 25.57 KB
kataw@0.0.81 297.65 KB 291.29 KB 59.47 KB
cherow@1.6.9 300.63 KB 89.85 KB 25.12 KB
@azariasb/escaya@0.0.63 98.24 KB 96.53 KB 25.97 KB
tenko@2.0.1 371.71 KB 142.41 KB 39.75 KB
tree-sitter@0.20.0 51.28 KB 22.81 KB 6.8 KB
tree-sitter-javascript@0.21.4 65.3 KB 40.06 KB 5.83 KB
Computing the package sizes may need NODE_OPTIONS=--openssl-legacy-provider depending on the state of crypto in your JavaScript VM. I had to keep meriyah and tree-sitter sizes from the previous update, because package-size wasn't able to compile their modern code.
The tree-sitter parser uses native libraries, which have to considered too, when computing the package size:
❯ node perf/tree-sitter-size.js
tree-sitter: 395.30 KB
tree-sitter-javascript: 389.42 KB
❯ package-size escodegen astring
package size minified gzipped
escodegen@2.1.0 279.28 KB 97.02 KB 25.68 KB
astring@1.8.6 36.07 KB 15.57 KB 4.32 KB
Estimating the size of @babel/generator failed with webpack compilation errors.
In lieu of a formal styleguide, take care to maintain the existing coding style. Lint and test your code.
Copyright (c) 2022-2024 Ferdinand Prantl
Licensed under the MIT license.