simplex-chat/apps/simplex-calculator-bot

SimpleX Calculator

A pocket calculator in a chat, built with the SimpleX Chat Node.js library.

Each user who connects via the bot's business address gets their own chat with a calculator message. The keys are bot commands: tapping a key sends it to the bot, and the bot replaces the calculator message with the updated one.

How it works

• Keys are applied left to right, without operator priority: 2 + 3 × 4 = gives 20.
• % follows Apple's calculator: 100 + 15 % shows 15, and = gives 115; 50 × 10 % shows 0.1, and = gives 5.
• C clears the current number; the second C clears the whole calculation.
• The display shows up to 15 digits, without exponent; larger results show Error.
• After =, the bot sends the calculation as a message, e.g. 2 + 2 = 4.
• Tapped keys are deleted from the chat; the calculation messages stay as a log.
• Users can also send messages instead of tapping keys:
  • a number or an expression, e.g. 12 × 3 + 4, is computed and entered as the current number, so 25, /add, 25, = gives 50.
  • a key, e.g. +, =, x, *, /, add or c, works as the tapped key.
• The calculator turns off after 10 minutes without use: the number is removed from the display, the keys stay. Any key, number or /calc turns it on.
• Apps that support commands made of symbols (chat protocol version 21) get keys like /+; older apps get keys like /add.

Install & build

cd apps/simplex-calculator-bot
npm install
npm run build

The bot requires a simplex-chat library version that passes the chat API to event handlers (7.1.0-beta.4.1 or later). To run against the in-tree library:

# In packages/simplex-chat-nodejs
npm link

# In apps/simplex-calculator-bot
npm link simplex-chat

Run

npm start

The bot prints its address on start. The database is stored in ./data.

Test

npm test

The end-to-end test runs a local SMP server with the TLS certificates from tests/fixtures/tls. On Linux, the test downloads smp-server from simplexmq releases to node_modules/.cache on the first run. To use another build, or on other systems, pass its path in SMP_SERVER variable:

SMP_SERVER=/path/to/smp-server npm test