common-shakeify
v1.1.2
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browserify tree shaking plugin using @indutny common-shake
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common-shakeify
browserify tree shaking plugin based on common-shake, the CommonJS tree shaker originally by @indutny.
Comments out unused exports from CommonJS modules.
With input files:
// math.js
exports.min = function (a, b) { return a < b ? a : b }
exports.max = function (a, b) { return a < b ? b : a }
// app.js
var math = require('./math')
console.log(math.max(10, 20))
This plugin will rewrite the files to:
// math.js
/* common-shake removed: exports.min = */ void function (a, b) { return a < b ? a : b }
exports.max = function (a, b) { return a < b ? b : a }
// app.js
var math = require('./math')
console.log(math.max(10, 20))
Use a minifier on the output to remove the exports entirely.
Install
npm install --save-dev common-shakeify
Usage
With the browserify cli:
browserify -p common-shakeify /my/app.js > bundle.js
# Minify
uglify-js bundle.js --compress > bundle.min.js
With the browserify Node API:
var commonShake = require('common-shakeify')
var b = browserify({ entries: '/my/app.js' })
.plugin(commonShake, { /* options */ })
.bundle()
// Minify & save
var uglify = require('minify-stream')
b
.pipe(uglify())
.pipe(fs.createWriteStream('bundle.min.js'))
Note that using a minifier transform like uglifyify doesn't eliminate the commented-out exports. Transforms run before common-shakeify, so you have to use a minifier on the final bundle to remove the unused exports.
Options
verbose
, v
When true, print messages to stderr when exports are deleted, or the tree-shaker bails out on a module.
Default false.
The verbose
flag only works when no custom handlers are passed, so if you're using eg. a custom onExportDelete
you have to print these messages manually.
$ browserify -p [ common-shakeify -v ] app.js > bundle.js
common-shake: removed `decode` in node_modules/vlq/dist/vlq.js:10:7
common-shake: bailed out: `module.exports` assignment in node_modules/process-nextick-args/index.js:20:3
onExportDelete(filename, exportName)
Handler called for every exported identifier that is being removed.
filename
is the path to the file that exports the identifier. exportName
is the name of the identifier. Return false to bail and keep the identifier.
onModuleBailout(module, reasons)
Handler called when a module cannot be tree-shaked for some reason.
module
is the Module object from common-shake.
reasons
is an array of reasons that caused this module to be deoptimised.
onGlobalBailout(reasons)
Handler called when tree-shaking is skipped entirely, usually because there is a dynamic require
call in the source.
reasons
is an array of reasons for skipping tree-shaking.
ecmaVersion
Parse with this ecmaVersion as interpreted by acorn. (default: 10)