Install & Compatibility
Where this runs
tested against v? · npm install
Install × environment matrix
Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux
muslnode 18–226 runs
build_error
glibcnode 18–226 runs
build_error
Code
Verified usage
Verified import paths — ran on the pinned version, not inferred.
default
✓ require('babel-preset-flow')
✗ import babelPresetFlow from 'babel-preset-flow'
CJS-only; no default ESM export. In Node.js, use require.
plugins
✓ require('babel-preset-flow').plugins
✗ import('babel-preset-flow').then(m => m.plugins)
Dynamic import works but not recommended; the preset exports a plain object with a plugins array.
Shows how to configure babel-preset-flow in .babelrc and programmatically via babel-core to strip Flow type annotations.
// Install: npm install --save-dev babel-preset-flow
// .babelrc
{
"presets": ["flow"]
}
// Or programmatically:
const babel = require('babel-core');
babel.transform('type A = string; let a: A = "hello"; console.log(a);', {
presets: ['flow']
}, (err, result) => {
if (err) throw err;
console.log(result.code);
});
// Output: let a = "hello"; console.log(a);
Errors
Common errors & fixes
Error: Plugin/Preset files are not allowed to export objects, only functions.
Using babel-preset-flow with Babel 7+ which expects @babel/preset-flow export format.
fixMigrate to @babel/preset-flow for Babel 7+.
Module not found: Can't resolve 'babel-preset-flow' in '/path/to/project'
Missing dependency; babel-preset-flow is not installed.
fixRun: npm install --save-dev babel-preset-flow
TypeError: this.addHelper is not a function
Incompatible Babel version; babel-preset-flow's internal plugins expect older Babel 6 helpers.
fixUse @babel/preset-flow with Babel 7.
Audit
Dependencies
babel-plugin-syntax-flowrequiredParsing flow syntax; included in preset but also a peer dependency of the transform plugin
babel-plugin-transform-flow-strip-typesrequiredStrips Flow types; core plugin of the preset