@nevware21/tripwire-chai

Chai.js compatibility shim powered by tripwire - Drop-in replacement for Chai's assert API.

Chai v5.x Compatible - Designed to match the Chai v5.x assert API

Purpose

Migrate from Chai.js without rewriting your tests. Perfect when:

• Chai dependencies are causing build issues
• You need Web Worker support (broken in some Chai versions)
• Your project is stuck due to Chai dependency conflicts
• You want to unblock your tests and migrate gradually

Note: This is NOT a complete Chai replacement. Only the assert.* API is implemented. The expect and should APIs are NOT available.

Installation

npm install @nevware21/tripwire-chai --save-dev

Recommended version range:

{
  "devDependencies": {
    "@nevware21/tripwire-chai": ">= 0.1.8 < 2.x"
  }
}

Quick Migration

Step 1: Update imports

- import { assert } from 'chai';
+ import { assert } from '@nevware21/tripwire-chai';

Step 2: Run your tests

Most assert.* functions should work immediately.

Step 3: Fix error message tests (if any)

Error messages differ from Chai. Use regex instead of exact strings:

- assert.throws(() => fn(), "exact chai message");
+ assert.throws(() => fn(), /error message/);

What's Supported?

Fully Implemented (assert API)

• Basic: equal, notEqual, strictEqual, deepEqual, isOk, isTrue, etc.
• Types: isObject, isArray, isString, isNumber, isBoolean, isFunction, isNull, isUndefined, isNaN, isFinite, etc.
• Comparisons: isAbove, isAtLeast, isBelow, isAtMost, closeTo, approximately, operator
• Properties: property, deepProperty, nestedProperty, ownProperty with value validation
• Collections: include, deepInclude, nestedInclude, ownInclude, deepOwnInclude, members, sameMembers, keys
• Deep Keys: hasAnyDeepKeys, hasAllDeepKeys, containsAllDeepKeys, doesNotHaveAnyDeepKeys, doesNotHaveAllDeepKeys for Maps/Sets with object keys
• Size: lengthOf, sizeOf
• Changes: changes, increases, decreases with delta tracking
• Errors: throws, doesNotThrow, ifError
• State: isExtensible, isSealed, isFrozen, isEmpty

NOT Implemented

• expect API - Use core @nevware21/tripwire instead
• should API - No plans to implement
• Plugins - use() function not available

Usage Example

import { assert } from '@nevware21/tripwire-chai';

// Your existing Chai tests should work
assert.equal(1 + 1, 2);
assert.isArray([1, 2, 3]);
assert.deepEqual({ a: 1 }, { a: 1 });
assert.throws(() => { throw new Error(); });
assert.property({ a: 1 }, 'a');
assert.include([1, 2, 3], 2);

Documentation

Migration Guide & Examples: Documentation Guide

Migrating from Chai: Migration Guide - Complete guide for upgrading from Chai.js to Tripwire

API Reference: TypeDoc Documentation

Core Package: @nevware21/tripwire - Consider migrating for better features

Repository: github.com/nevware21/tripwire

When to Use Core Tripwire

Consider switching to @nevware21/tripwire for:

• Better error messages
• Fluent expect syntax
• New features and improvements
• Long-term maintenance

Browser Support

• Comprehensive support from ES5+ for broad compatibility
• Tested in Node.js, browsers, and Web Workers

Contributing

See Contributing Guide

License

This project is licensed under the MIT License. See the LICENSE file for details.