Registry / serialization / babel-plugin-tcomb

babel-plugin-tcomb

library0.4.0jsnpmunverified

Babel plugin that adds runtime type checking from Flow annotations using tcomb. Version 0.4.0, released 2020-09-05. This is the latest stable release; prior versions support Babel 6, latest supports Babel 7. Transforms Flow type annotations into runtime assertions via tcomb. Different from flow-remove-types or babel-plugin-transform-flow-strip-types because it keeps the type information for runtime validation. Works alongside Flow for hybrid static + dynamic checking. Supports refinement types, immutability enforcement, and IO boundary validation. Abandoned as of November 2021; no commits or releases since 0.4.0.

serialization testing

npm install babel-plugin-tcomb

github ↗package ↗

INSTALL

IMPORT

SIG · BABEL-PLUGIN-TCOMB

babel-plugin-tcomb

serializationjavascriptv0.4.0

Install

—

Import

—

Disk

—

Pass rate

0/ 6

Env Coverage0 / 6

glibc

18–22

musl

18–22

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

musl

node 18–226 runs

build_error

glibc

node 18–226 runs

build_error

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

default

✓ // .babelrc { "plugins": ["tcomb"] }

The plugin is used as a Babel plugin, not imported directly in source code.

tcomb

✓ import t from 'tcomb'

✗ import { t } from 'tcomb'

tcomb is a CommonJS module with default export; ES6 default import works with Babel.

Flow type annotations

✓ function add(a: number, b: number): number { return a + b; }

✗ function add(a, b) { return a + b; }

Without annotations, no runtime checks are generated. Annotations must be Flow-standard.

Shows Babel setup and runtime type checking triggered by a Flow-annotated function call with a type mismatch.

// .babelrc { "plugins": [ "syntax-flow", "tcomb", "transform-flow-strip-types" ] } // src/index.js function sum(a: number, b: number): number { return a + b; } // This will throw at runtime: sum(1, 'x'); // Uncaught TypeError: [tcomb] Invalid value "x" supplied to b: Number

Debug

Known issues

breakingVersion 0.4.0 requires Babel 7; incompatible with Babel 6 projects.

fix

Upgrade to Babel 7 or pin to 0.3.27 for Babel 6.

affects: 0.4.0

deprecatedPackage is no longer maintained; last release 0.4.0 (2020). No bug fixes or updates for newer Babel versions.

fix

Consider alternatives like babel-plugin-runtime-typecheck or TypeScript with ttypescript.

affects: >=0.4.0

gotchatcomb must be requireable at runtime; if using ES modules, ensure transform-modules-commonjs or similar is applied before tcomb plugin.

fix

Add plugin order: transform-modules-commonjs before tcomb, or use Babel env with modules: 'commonjs'.

affects: >=0.3.0

gotchaPassing passPerPreset: true may be required when using multiple presets to avoid conflicts.

fix

Set passPerPreset: true in .babelrc.

affects: >=0.3.0

breakingRemoved support for Babel 6 in v0.4.0; no migration path for Babel 6 projects.

fix

Stick with v0.3.27 for Babel 6, or upgrade entire project to Babel 7.

affects: 0.4.0

Errors

Common errors & fixes

Error: Cannot find module 'tcomb'

tcomb is a peer dependency and not installed automatically.

fix

npm install --save-dev tcomb

TypeError: [tcomb] Invalid value "x" supplied to b: Number

Runtime type check failed – argument type mismatch.

fix

Correct the call to pass a number: sum(1, 2);

Error: Plugin 0 specified in "..." provided an invalid property of type "..."

Plugin order or misconfiguration in .babelrc.

fix

Ensure plugins array contains 'tcomb' after 'syntax-flow' and before 'transform-flow-strip-types'. Try passPerPreset: true.

ReferenceError: t is not defined

tcomb not imported or requireable in your source module.

fix

Add import t from 'tcomb' at the top of your file, or ensure CommonJS require('tcomb') works.

Upgrade

Version history

0.4.0latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

17 hits · last 30 days

node

OpenAI (training)

Resources

githubhttps://github.com/gcanti/babel-plugin-tcomb ↗

packagehttps://www.npmjs.com/package/babel-plugin-tcomb ↗