Registry / testing / istanbul-middleware-ts

istanbul-middleware-ts

library1.1.4jsnpmunverified

istanbul-middleware-ts is a TypeScript-first middleware designed for integrating Istanbul code coverage reporting into Node.js applications, primarily with Express.js. It provides HTTP endpoints to collect, reset, merge, report, and download code coverage data. The package is currently at version 1.1.4, indicating active maintenance with several recent minor releases, and offers complete TypeScript support with type definitions. Its release cadence appears to be driven by feature additions and bug fixes within the 1.x series. A key differentiator is its modern TypeScript implementation that is compatible with the API of the original `istanbul-middleware`, making it a drop-in replacement for users seeking enhanced type safety and up-to-date Node.js practices. It offers robust functionality for CI/CD pipelines and local development environments by enabling dynamic coverage data management, HTML report generation, and LCOV/ZIP package downloads, alongside features like differential coverage reporting against git targets.

testing devops web-framework

npm install istanbul-middleware-ts

github ↗package ↗

INSTALL

IMPORT

SIG · ISTANBUL-MIDDLEWAR

istanbul-middleware-ts

testingjavascriptv1.1.4

Install

—

Import

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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.

createHandler

✓ import { createHandler } from 'istanbul-middleware-ts';

✗ const { createHandler } = require('istanbul-middleware-ts');

Primary export for middleware creation, typically used with Express.js `app.use()`.

getCoverageObject

✓ import { getCoverageObject } from 'istanbul-middleware-ts';

✗ const { getCoverageObject } = require('istanbul-middleware-ts');

Use for programmatic access to the current collected Istanbul coverage data object.

resetCoverage

✓ import { resetCoverage } from 'istanbul-middleware-ts';

✗ const { resetCoverage } = require('istanbul-middleware-ts');

Use for programmatic resetting of the coverage data collected by the middleware.

This example sets up an Express.js server with the Istanbul middleware, making coverage reports and data available at the `/coverage` endpoint, and enabling GET requests to reset coverage.

import express from "express"; import { createHandler } from "istanbul-middleware-ts"; const app = express(); // Add Istanbul middleware app.use( "/coverage", createHandler({ resetOnGet: true // Allow GET requests to reset coverage }) ); app.listen(3000, () => { console.log("Server running on http://localhost:3000"); console.log("Coverage available at http://localhost:3000/coverage"); });

Debug

Known issues

gotchaThe `/reset` endpoint accessible via GET requests is disabled by default for security reasons and to prevent accidental data loss. It must be explicitly enabled.

fix

Pass `{ resetOnGet: true }` to the `createHandler` options to enable `GET /reset` functionality.

affects: >=1.0.0

gotchaDifferential coverage functionality (GET /diff, GET /diff/info) requires the Python `diff-cover` package to be installed globally or available in the system's PATH, and the `diffTarget` option to be configured.

fix

Install `diff-cover` (e.g., `pip install diff-cover`) and configure the `diffTarget` option in the `createHandler` options to a branch, commit, or tag.

affects: >=1.0.0

Errors

Common errors & fixes

Cannot find module 'express' or its corresponding type declarations.

Express.js is a peer dependency and must be installed separately by your project.

fix

Install Express.js and its type definitions: `npm install express @types/express`

TypeError: app.use is not a function

Attempting to use the `istanbul-middleware-ts` handler without a valid Express application instance.

fix

Ensure `app` is an instance of `express()` before calling `app.use()`.

ReferenceError: require is not defined in ES module scope

Using CommonJS `require` syntax in a TypeScript or ES Module project (e.g., `package.json` `"type": "module"` or `.mjs` files).

fix

Use ES module import syntax: `import { createHandler } from 'istanbul-middleware-ts';`

Upgrade

Version history

1.1.4latest on npm

Audit

Dependencies

expressrequiredRequired for middleware integration with Express.js applications.

diff-coveroptionalRequired for differential coverage reports if `diffTarget` option is configured and `enableDiffCoverage` is true.

Agent activity

4 hits · last 30 days

node

Resources

githubhttps://github.com/129tyc/istanbul-middleware-ts ↗

packagehttps://www.npmjs.com/package/istanbul-middleware-ts ↗