Automatically build a dat gui from a javascript object

datgui-build.js

config = { //SAMPLE OBJECT - replace this with your data object
  stroke: 2, //svg stroke value
  opacity: 0.3, //0-1
  offsetX: 120, //px
  offsetY: 80,
  fontWeight: 400, //css font-weight
  fontSize: 12, //in px
  changePositive: '\u25B4', //unicode character for up arrow
  changeNegative: '\u25BE', //unicode character for down arrow
  colorBlue: '#1190A3', //all hex colors will automatically use the addColor dat gui function
  timings: {
      delay: 1000, //in ms
  }
}

class guiBuilder {
  
  constructor() {
      this.buildGUI();
  }
  
  buildGUI(){
    this.gui = new dat.GUI();

    this.guiFolder = this.gui.addFolder('My Folder');
    this.gui.remember(config);
    this.addToGui(config, this.guiFolder);
    
    //add a button to be able to update your scene with changed variables if they don't auto-update things on screen
    const guiUpdate = {
        update: () => { //when button pressed, animation will restart with updated values
            this.restartAnimation();
        }
    };
    this.gui.add(guiUpdate, 'update');
  }
  
   addToGui(obj, folder) {
     for (const key in obj) { //for each key in your object
        if (obj.hasOwnProperty(key)) {
            let val = obj[key];
            if (typeof val == 'number') { //if the value of the object key is a number, establish limits and step
                const numDigits = this.getNumDigits(val);
                let step, limit;
                if (val > -1 && val < 1) { //if it's a small decimal number, give it a GUI range of -1,1 with a step of 0.1...
                    step = 0.1;
                    limit = 1;
                } else { //otherwise, calculate the limits and step based on # of digits in the number
                    const numDigits = this.getNumDigits(Math.round(val)); //to establish a step and limit, we'll use a base number that is an integer
                    limit = Math.pow(10, numDigits); //make the limit one digit higher than the number of digits of the itself, i.e. '150' would have a range of -1000 to 1000...
                    step = Math.pow(10, numDigits - 2); //...with a step one less than the number of digits, i.e. '10'
                }
                folder.add(obj, key, -limit, limit).step(step); //add the value to your GUI folder
            } else if (typeof val === 'object') {
                this.addToGui(val, folder); //if the key is an object itself, call this function again to loop through that subobject, assigning it to the same folder
            } else {
                if (val.startsWith('#')) { //if it's a HEX value, we're going to assume it's a color. You could run a more advanced check here
                    folder.addColor(obj, key);
                } else { //just add the value to the folder with no specific step, and let dat GUI interpret it as it sees fit...
                    folder.add(obj, key); //...this would include things like boolean values as checkboxes, and strings as text fields
                }

            }
        }
    }
  }
  
  getNumDigits(val) {
    return (`${val}`.match(/\d/g) || []).length //a regex to compute the number of digits in a number. Note that decimals will get counted as digits, which is why to establish our limit and step we rounded
  }
  
  restartAnimation(){
    //your restart / teardown code here
  }

}

window.guiBuilder = new guiBuilder();