Show HN: I made a web-based notepad with a built in unit calculator

1. decimal.js

   1 22 6,767 5.3 JavaScript

   An arbitrary-precision Decimal type for JavaScript

   

   Looks good! I love the idea of the embedded calculator

   I noticed that it doesn't handle remainder/modulo (%) equations:

   "10 % 2" results in: "Left hand side of addition cannot be a percentage."

   It does look like decimal.js can handle that: https://mikemcl.github.io/decimal.js/#mod

   https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe...

2. SurveyJS

   surveyjs.io featured

   JavaScript Form Builder with No-Code UI & Built-In JSON Schema Editor. Add the SurveyJS white-label form builder to your JavaScript app (React/Angular/Vue3). Build complex JSON forms without coding. Fully customizable, works with any backend, perfect for data-heavy apps. Learn more.

   

3. notecalc3

   2 9 1,162 3.5 Rust

   NoteCalc is a handy calculator trying to bring the advantages of Soulver to the web.

   

   Very cool!

   This reminds me of the open source NoteCalc: https://bbodi.github.io/notecalc3/

   It was discussed on HN, you might look there for inspiration: https://news.ycombinator.com/item?id=25495393

4. numi

   3 52 6,007 4.2 JavaScript

   Beautiful calculator app for macOS, Linux & Windows

   

   Very nice! Reminds me a lot of numi (https://numi.app). Similar, but MacOS only (and paid).

5. recomputer

   4 5 10 5.2 TypeScript

   A smart calculator web app

   

6. CalcPad

   5 2 30 4.0 TypeScript

   A different take on the caculator (by filipesabella)

   

   I've made this one and use it daily:

   https://github.com/filipesabella/calcpad

   It's electron though, if that's important to you.

7. human_calc

   6 3 2 5.0 Python

   Calculator that processes formulas like a human

   

   Along the same lines, I made a command line calculator that does basic unit conversions, and has a few other tricks up it's sleeve

   https://github.com/seligman/human_calc

   I find it surprisingly useful. It's probably one of those things that has an audience of one, but I find it useful.

8. insect

   7 25 3,179 1.8 PureScript

   Discontinued High precision scientific calculator with support for physical units

   

9. InfluxDB

   www.influxdata.com featured

   InfluxDB – Built for High-Performance Time Series Workloads. InfluxDB 3 OSS is now GA. Transform, enrich, and act on time series data directly in the database. Automate critical tasks and eliminate the need to move data externally. Download now.

   

10. mathjs

    8 23 14,738 9.4 JavaScript

    An extensive math library for JavaScript and Node.js

    

    Ha, yes, I was being nosy. It was quite easy to spot as it's the only XHR/Fetch request.

    I was intrigued what you had used to build it, and if you had built your own solver (which you have), and what editor you used (Code Mirror) so went looking at the code. Interesting to see you left the source maps for production, made it easy for my sleuthing...

    I experimented with a similar idea last year, but used ProseMirror/TipTap as the editor to enable rich text editing, and the MathJS (https://mathjs.org) solver. I also combined it with PouchDB and Yjs for offline editing and syncing between devices. Never finished it though, you have kept your nice and simple!

11. eulalie

    9 1 71 10.0 JavaScript

    ES6 flavoured parser combinators

    

12. MarkdownFormula

    10 3 23 1.8 TypeScript

    Use Excel-like formulas in markdown tables

    

13. moo

    11 1 851 2.4 JavaScript

    Optimised tokenizer/lexer generator! 🐄 Uses /y for performance. Moo. (by no-context)

    

14. redbean-calcpad

    12 1 14 0.0 Makefile

    CalcPad served with redbean

    

    I wanted to see how this would run in redbean[1], and it runs fantastically!

    If you wanna see this in a little executable that you can pass around to your friends, check out this repo I threw up: https://github.com/shmup/redbean-calcpad

    1. https://justine.lol/redbean2/

15. Joplin

    13 783 49,222 9.9 TypeScript

    Joplin - the privacy-focused note taking app with sync capabilities for Windows, macOS, Linux, Android and iOS.

    

    That's really cool!

    Anyone knows if there's a way to have this feature in Joplin[0] ?

    [0]: https://joplinapp.org/

16. note-parser

    14 1 2 3.3 TypeScript

    A plain-text parser (in early stages).

    

    Hey!

    It's still in development. I built a proof-of-concept from scratch almost a year ago, which I just open-sourced at the following link.

    https://github.com/nonoesp/note-parser

    I intend to develop it a bit more and host it online.

    A previous prototype, really barebones, is at https://expensed.me.

    The idea is to drag and drop (or type) a plain-text note and visualize the data as a scatterplot or other charts.

17. SoulverCore

    15 2 923 6.2 Swift

    A powerful Swift framework for evaluating natural language math expressions

    

18. libqalculate

    16 57 2,082 8.9 C++

    Qalculate! library and CLI

    

    Note: I had this response typed up but didn't submit...

    One related app that I absolutely love is Qalculate![1] (yes, it has a built-in exclamation for default enthusiasm :) )

    It can do cool stuff like converting N (newtons) to kg.m/s^2 when you specify units as ?kg. It also converts units like 1kW x 1year = 31.55... GJ

    It's fantastic for engineering and specially back-of-envelope calculations. This notepad aspect does seem useful though. One alternative is to use Jupyter notebooks, sometimes I work problems with Sage[2]+Jupyter. Sage is extremely powerful (you can do calculus, linear algebra, and more) but doesn't support units (that I know of), it's more geared toward advanced maths.

    [1] https://qalculate.github.io/

    [2] https://www.sagemath.org/ It's a bit on the heavy side although it's definitely worth it if you're doing a lot of math. I think the flatpak is preferred due to its significant size.

19. liveCalc

    17 1 3 4.0 JavaScript

    having fun with arithmetic

    

20. SaaSHub

    www.saashub.com featured

    SaaSHub - Software Alternatives and Reviews. SaaSHub helps you find the best software and product alternatives

    

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