gulp-babel-istanbul

1.6.0 verified Sat Apr 25 auth: no javascript maintenance

A gulp plugin that instruments source files with Istanbul code coverage after Babel transpilation, enabling ES2015+ coverage reporting. Version 1.6.0 (latest) uses babel-istanbul under the hood. It integrates with any Node.js test framework via gulp, providing hooks for require and reports. Compared to alternatives like gulp-istanbul, it natively handles Babel-transpiled code. Browser testing is untested. Requires gulp, babel, and Istanbul. Slow release cadence; last update 2016. Consider seamless builds with webpack or karma for browser coverage.

Common errors

error Error: Cannot find module 'babel/register' ↓

cause Plugin expects babel-istanbul but babel-core is not installed or outdated

fix

npm install babel-core@^6 --save-dev

error TypeError: istanbul.hookRequire is not a function ↓

cause hookRequire is not called on the default export directly

fix

Use require('gulp-babel-istanbul').hookRequire or import { hookRequire } from 'gulp-babel-istanbul'

error ENOENT: no such file or directory, open 'coverage/lcov.info' ↓

cause writeReports expects a coverage variable that may not exist

fix

Ensure istanbul() and hookRequire() are applied before running tests

error The coverage report is empty ↓

cause includeUntested option false by default and require hook not applied

fix

Set { includeUntested: true } and ensure hookRequire() is piped

Warnings

gotcha hookRequire must be used in the same stream after istanbul() ↓

fix Call .pipe(istanbul.hookRequire()) before the finish event.

gotcha Browser testing is untested and may not work ↓

fix Use Karma with karma-coverage instead for browser coverage.

deprecated babel-core is replaced by @babel/core ↓

fix Use gulp-babel with @babel/core and @babel/preset-env; this plugin uses babel-istanbul which may not be updated.

gotcha require hook does not work with ESM modules ↓

fix Use CommonJS modules or transpile to CJS before testing.

Install

npm install gulp-babel-istanbul

yarn add gulp-babel-istanbul

pnpm add gulp-babel-istanbul

Imports

istanbul

wrong

const istanbul = require('gulp-babel-istanbul').default

correct

import istanbul from 'gulp-babel-istanbul'

Default export is the istanbul function. CommonJS require is fine.

hookRequire

wrong

require('gulp-babel-istanbul').hookRequire

correct

import { hookRequire } from 'gulp-babel-istanbul'

Available as named export from the same module.

writeReports
wrong
```
istanbul.writeReports()
```
correct
```
import { writeReports } from 'gulp-babel-istanbul'
```
writeReports is a named export, not a method on the default export.

Quickstart

Shows complete gulp task for instrumenting ES2015 source, running mocha tests, and generating coverage reports with threshold enforcement.

const gulp = require('gulp');
const babel = require('gulp-babel');
const istanbul = require('gulp-babel-istanbul');
const mocha = require('gulp-mocha');

gulp.task('coverage', function (cb) {
  gulp.src('src/**/*.js')
    .pipe(istanbul())
    .pipe(istanbul.hookRequire())
    .on('finish', function () {
      gulp.src('test/**/*.js')
        .pipe(babel())
        .pipe(mocha())
        .pipe(istanbul.writeReports())
        .pipe(istanbul.enforceThresholds({ thresholds: { global: 90 } }))
        .on('end', cb);
    });
});