tinyexpect

expect is a lightweight testing utility with 0 dependencies that provides a Jest-like assertion API for TypeScript/JavaScript projects that use the native Node.js test runner node --test.

API Reference

Matchers

• toBe(value): Checks strict equality (including deep equality for objects)
• toNotBe(value): Checks strict inequality
• eitherOr(values[]): Checks if value is included in an array of possible values
• toBeNumber(): Verifies value is a number
• toBeNumberOrParsed(): Verifies value is either a number or can be parsed as one
• toBeNumberOr(values[]): Verifies value is either a number or one of the specified strings
• toBeFalsy(): Checks if value is falsy
• toBeTruthy(): Checks if value is truthy
• toBeDefined(): Verifies value is not undefined
• toContainString(str): Checks if string contains a substring
• toNotContainString(str): Checks if string does not contain a substring

Error Handling

All matchers throw descriptive errors when assertions fail, including:

• Detailed error messages for object comparisons
• Type mismatch notifications
• Clear expected vs actual value reporting

License

MIT