minify: Cannot read property 'add' of undefined

seeing " Cannot read property ‘add’ of undefined" with the latest

sample code, junk.js

const y = () => {};
function x(foo = y) {}

command: npx babel junk.js --presets=minify

package.json

{
  "name": "babelbug",
  "version": "1.0.0",
  "description": "",
  "devDependencies": {
    "@babel/core": "^7.7.0",
    "@babel/preset-env": "^7.7.0",
    "@babel/cli": "^7.7.0",
    "babel-preset-minify": "~0.5.0"
  }
}

stack

{ TypeError: C:\babelbug\junk.js: Cannot read property 'add' of undefined
    at ScopeTracker.addReference (C:\babelbug\node_modules\babel-plugin-minify-mangle-names\lib\scope-tracker.js:47:34)
    at ReferencedIdentifier (C:\babelbug\node_modules\babel-plugin-minify-mangle-names\lib\index.js:196:26)
    at newFn (C:\babelbug\node_modules\@babel\traverse\lib\visitors.js:220:17)
    at bfsTraverse (C:\babelbug\node_modules\babel-plugin-minify-mangle-names\lib\bfs-traverse.js:32:43)
    at Mangler.collect (C:\babelbug\node_modules\babel-plugin-minify-mangle-names\lib\index.js:229:7)
    at Mangler.run (C:\babelbug\node_modules\babel-plugin-minify-mangle-names\lib\index.js:54:12)
    at PluginPass.exit (C:\babelbug\node_modules\babel-plugin-minify-mangle-names\lib\index.js:558:19)
    at newFn (C:\babelbug\node_modules\@babel\traverse\lib\visitors.js:179:21)
    at NodePath._call (C:\babelbug\node_modules\@babel\traverse\lib\path\context.js:55:20)
    at NodePath.call (C:\babelbug\node_modules\@babel\traverse\lib\path\context.js:42:17) code: 'BABEL_TRANSFORM_ERROR' }

About this issue

Original URL
State: open
Created 4 years ago
Reactions: 19
Comments: 23

Commits related to this issue

Switch to using terser instead of babel Babel has this bug which appeared after trying to update to the latest version, and remained even after rolling back to an older version. Extremely annoying. ... — committed to fwextensions/QuicKey by fwextensions 3 years ago
Release v1.6.1 Fix #57. Squashed commit of the following: commit d10eca3c60d70e6bfd52bcd451b81fd7f4146fe6 Author: John Dunning <fw@johndunning.com> Date: Tue May 4 15:54:50 2021 -0700 Update... — committed to fwextensions/QuicKey by fwextensions 3 years ago

Most upvoted comments

I was able to work around this problem by using @babel/plugin-transform-parameters to transpile away the default parameters syntax prior to minification. I would still be interested to see the bug fixed though.

s100 on Feb 11, 2021

The issue seems to be with default functional parameters set to a constant.

mjakobis on Jan 21, 2020

I see the same issue when using rollup-babel-minify. Dependabot tried to update to latest babel and couldn’t due to this issue.

TypeError: unknown: Cannot read property 'add' of undefined
    at ScopeTracker.addReference (/Users/jeffyates/git/checksync/node_modules/babel-plugin-minify-mangle-names/lib/scope-tracker.js:47:34)
    at ReferencedIdentifier (/Users/jeffyates/git/checksync/node_modules/babel-plugin-minify-mangle-names/lib/index.js:196:26)
    at newFn (/Users/jeffyates/git/checksync/node_modules/@babel/traverse/lib/visitors.js:220:17)
    at bfsTraverse (/Users/jeffyates/git/checksync/node_modules/babel-plugin-minify-mangle-names/lib/bfs-traverse.js:32:43)
    at Mangler.collect (/Users/jeffyates/git/checksync/node_modules/babel-plugin-minify-mangle-names/lib/index.js:229:7)
    at Mangler.run (/Users/jeffyates/git/checksync/node_modules/babel-plugin-minify-mangle-names/lib/index.js:54:12)
    at PluginPass.exit (/Users/jeffyates/git/checksync/node_modules/babel-plugin-minify-mangle-names/lib/index.js:558:19)
    at newFn (/Users/jeffyates/git/checksync/node_modules/@babel/traverse/lib/visitors.js:179:21)
    at NodePath._call (/Users/jeffyates/git/checksync/node_modules/@babel/traverse/lib/path/context.js:55:20)
    at NodePath.call (/Users/jeffyates/git/checksync/node_modules/@babel/traverse/lib/path/context.js:42:17)

somewhatabstract on Feb 17, 2020

Seeing the same problem here… setting mangle: false in the options seems to work-around the problem.

arantes555 on Feb 5, 2020

Any update? I found that it started to fail after a change in @babel/types@7.8.0 - https://github.com/babel/babel/pull/10917 Hopefuly https://github.com/babel/minify/pull/1024 will be merged soon.

ochodek on Mar 10, 2023

Any update? Seem there is an PR checked but not merged.

dhlolo on Jul 25, 2022

I got same error.

ruymaster on Apr 18, 2021

Same issue here to build webtorrent

DiegoRBaquero on Apr 1, 2020