Mini-Calc Desklet

UUID: calc@ptandler
Last edited:
2 months ago 2021-09-21, 06:59
Last commit: [343b57e7] added icon.png

Very simple and minimalistic but yet powerful calculator that evaluates JavaScript expressions.

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Mini-Calculator Desklet based on JavaScript Expressions

Very simple and minimalistic but yet quite powerful calculator that evaluates JavaScript expressions. The complete power of JS directly at your hand! ;-)

Keyboard Input

Keyboard input is available after the desklet was raised to top by the defined shortcut (default SUPER+C, can be changed in the desklet settings).

Features and Example Expressions

  • 1+2 = 3
  • (1 + 2) * (3 + 4) = 21
  • All functions defined in the JavaScript Math object are included using the with statement (knowing that is not generally recommended using with in JS, but I think here it's kind of convenient).
    • min(1,2) = 1
    • max(1,2) = 2
    • sqrt(16) = 4
    • abs(-1) = 1
    • The trigonometric functions sin(), cos(), tan(), asin(), acos(), atan(), and atan2() expect (and return) angles in radians.
    • Helper functions: degToRad(180) = approx. 3.14, radToDeg(PI) = 180
    • random() returns a pseudo-random number between 0 and 1.
    • Euler's constant: E = approx. 2.718
    • PI = approx. 3.14159
  • You can define variables; this expression will return the assigned value. The variables will keep their value until the desklet is restarted:
    • a=2 = 2
  • You can use the comma , operator to evaluate several expressions and return just the value of the last one. Can be used to define variables:
    • a=2, b=3, a*b
  • For conditional expression you can use the JS ? : operator, e.g. 1 < 2 ? "that's true" : "no, wrong"
  • You can define functions:
    • fib = (n) => n <= 0 ? 0 : (n <= 1 ? 1 : (fib(n - 1) + fib(n - 2))), fib(7) = 13
  • You can use all builtin JavaScript functions and global objects (available in GJS / CJS), such as JSON.stringify

ToDo: Ideas for Further Development

  • add expression & result history as dropdown with scrollbar (on pressing "enter" + clear text input)
  • add action "copy value to clipboard" including keyboard shortcut; also allow copying the expression; and of course allow copying all past expressions and results from the history
  • add icon to open message box for documentation and introduction that explains some JS expression syntax (e.g. the examples above)
  • add translations (i18n)
  • add option to turn off to use JSON.stringify() to display results

Cinnamon Desklet Development hints

This is the first desklet and also first Gnome app I developed. It was a bit tricky for me to find helpful documentation. Here some things that were helpful for me.

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