Registry / testing / espower-typescript

espower-typescript

library10.0.1jsnpmunverified

espower-typescript is an instrumentation library that integrates `power-assert` with TypeScript projects, enabling rich, detailed assertion messages for test failures. It functions as a `mocha` `--require` hook, transforming TypeScript test files (`.ts`, `.tsx`) on the fly to inject power-assert's expressive assertions. The current stable version is 10.0.1. It aims to maintain compatibility with specific TypeScript versions (v2.7+ for v10.x) and Node.js environments (v10+), typically updating to align with major `ts-node` or `typescript` releases rather than a fixed cadence. Its key differentiators include a zero-config mode, automatic `tsconfig.json` detection, internal reliance on `ts-node` for compilation, and support for JSX/React and `allowJs` configurations.

testing web-framework

npm install espower-typescript

github ↗package ↗

INSTALL

IMPORT

SIG · ESPOWER-TYPESCRIPT

espower-typescript

testingjavascriptv10.0.1

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.

assert (Node.js built-in module)

✓ import assert = require('assert');

✗ import assert from 'assert';

For `power-assert` instrumentation to work correctly with `espower-typescript`, the CommonJS-style `require` syntax is mandatory for importing Node's built-in `assert` module. Direct ES module imports for `assert` will bypass instrumentation.

espower-typescript/guess (Mocha hook)

✓ mocha --require espower-typescript/guess

✗ import { guess } from 'espower-typescript';

This package is primarily consumed as a Mocha `--require` hook to preprocess TypeScript test files. It is not intended for direct JavaScript `import` statements within your application code.

@types/node

✓ npm install -D @types/node

When type checking is enabled (default since v9.0.0), TypeScript definition files for Node.js globals are often required to prevent compilation errors.

@types/mocha

✓ npm install -D @types/mocha

When type checking is enabled (default since v9.0.0), TypeScript definition files for Mocha globals are often required for test files.

Demonstrates how to install espower-typescript with its common peer dependencies and run a simple, failing TypeScript test with Mocha to show power-assert's detailed output.

npm install -D espower-typescript power-assert mocha typescript @types/node @types/mocha // test/test.ts import assert = require('assert'); describe('Array#join', () => { it('joins all elements into a string with separator', () => { // This assertion is intentionally designed to fail to demonstrate power-assert's output. assert(['a', 'b', 'c'].join(':') === 'a:b:c:'); }); }); // To run tests from your terminal: // ./node_modules/.bin/mocha --require espower-typescript/guess "test/**/*.ts" // Expected (failing) output will include detailed power-assert instrumentation: // AssertionError [ERR_ASSERTION]: # test.ts:6 // // assert(['a','b','c'].join(':') === 'a:b:c:') // | | | // ["a","b","c"] "a:b:c" false

Debug

Known issues

breakingespower-typescript v10.x and newer requires Node.js v10.x or higher. Older Node.js versions are no longer supported.

fix

Upgrade your Node.js environment to version 10 or newer.

affects: >=10.0.0

breakingespower-typescript v10.x and newer requires TypeScript v2.7 or higher. Ensure your project's `typescript` peer dependency meets this requirement.

fix

Update the `typescript` package in your project to version 2.7 or later (`npm install typescript@latest`).

affects: >=10.0.0

breakingSince v9.0.0, `typescript` must be installed as a local dependency in your project (e.g., `npm install -D typescript`), rather than relying on global installations or internal transitive dependencies.

fix

Explicitly add `typescript` to your project's devDependencies: `npm install -D typescript`.

affects: >=9.0.0

breakingFrom v9.0.0, type checking is enabled by default internally via `ts-node`. This requires `@types/node` and `@types/mocha` (or similar `@types` packages for other test runners) to be installed as devDependencies.

fix

Install necessary type definitions: `npm install -D @types/node @types/mocha`.

affects: >=9.0.0

gotchaYou MUST use `import assert = require('assert')` for Node.js's built-in `assert` module. Using `import assert from 'assert'` will prevent `power-assert` instrumentation from working correctly, resulting in generic assertion errors.

fix

Always use the CommonJS-style `import assert = require('assert')` for the assertion module when using `espower-typescript`.

affects: >=0.0.0

breakingThe internal `ts-node` dependency was updated from v8 to v9 in v10.0.0. Users relying on specific `ts-node` behaviors or configurations might need to review `ts-node`'s v9 release notes for compatibility.

fix

Consult the `ts-node` v9 release notes and adjust any `ts-node` specific environment variables or configurations if issues arise.

affects: >=10.0.0

Errors

Common errors & fixes

Cannot find module 'typescript'

`typescript` is a peer dependency but is not installed in the project or its version is incompatible.

fix

Install `typescript` as a devDependency: `npm install -D typescript`.

TS2307: Cannot find module '@types/node'

Type checking is enabled by default, and `@types/node` (or other required `@types` packages) is missing.

fix

Install the missing type definitions: `npm install -D @types/node`.

AssertionError: Expected true to be false

This is a generic assertion error, indicating that `power-assert` instrumentation failed. A common cause is using `import assert from 'assert'` instead of `import assert = require('assert')`.

fix

Ensure you are using `import assert = require('assert')` for the `assert` module in your test files.

Error: The 'mocha' command failed with exit code 1. You may need to update 'mocha' or 'espower-typescript'.

This can occur due to Node.js version incompatibility, especially with older Node.js versions no longer supported by `espower-typescript`.

fix

Verify your Node.js version is >=10.x. Update Node.js if necessary.

Upgrade

Version history

10.0.1latest on npm

Audit

Dependencies

typescriptrequiredPeer dependency for TypeScript compilation.

ts-noderequiredUsed internally for TypeScript compilation and runtime execution.

Agent activity

2 hits · last 30 days

node

Resources

githubhttps://github.com/power-assert-js/espower-typescript ↗

packagehttps://www.npmjs.com/package/espower-typescript ↗