This library hasn't been updated, and I've created a more powerful one called a-calc that you can try

[Autumn-one]

https://www.npmjs.com/package/a-calc

[Sander-Toonen]

This is another alternative:

https://github.com/Pro-Fa/expreszo-typescript

• Mostly compatible with expr-eval
• Has quite a lot of extra functionality
• Fully ported to typescript, modern tooling an extensive test coverage
• Uses a Pratt parser instead of a recursive parser which is a lot faster
• Contains a language service provider See playground example
• LSP functions are exposed to an MCP server too