Value resets back to maxvalue after hitting 0

Issue

I'm creating a calculator which shows how much the artist has left to pay to the recordcompany. In my code everytime 'artistCosts' reaches 0 it pops back up to the maximum value. This is my code:

  // als er bepaalde waarden wijzigen worden de berekeningen opnieuw uitgevoerd
  change() {
    console.log('change');
    this.calculateValues();
  }

  // wijziging in dealtype
  dealtypeChanged(value) {
    this.dealType = value;
    console.log(this.dealType);
    if (this.dealType == 'licentieDeal') {
      this.recordingCosts = 0;
      this.marketingCosts = 2000;
      this.splitArtist = 25;
    } else if (this.dealType == 'distributieDeal') {
      this.recordingCosts = 0;
      this.marketingCosts = 0;
      this.splitArtist = 80;
    } else if (this.dealType == 'eigenDeal') {
      this.splitArtist = 100;
      this.artistAdvance = 0;
      this.recordingCosts = 0;
      this.marketingCosts = 0;
    } else {
      this.splitArtist = 15;
      this.artistAdvance = 2000;
      this.recordingCosts = 2000;
      this.marketingCosts = 2000;
    }
    this.change();
  }

  // berekende en verdeeld kosten tussen label en artiest op basis van recoupable velden
  calculateCosts() {
    this.artistCosts = 0;
    this.labelCosts = this.artistAdvance + this.marketingCosts + this.recordingCosts;
    if (this.recoupableArtistAdvance === true) {
      this.artistCosts = this.artistCosts + this.artistAdvance;
    }
    if (this.recoupableMarketingCosts === true) {
      this.artistCosts = this.artistCosts + this.marketingCosts;
    }
    if (this.recoupableRecordingCosts === true) {
      this.artistCosts = this.artistCosts + this.recordingCosts;
    }
  }        

// Distributes revenue between artist and label via split
      divideRevenue() {
        let artistRevenue = (this.grossRevenue * (this.splitArtist / 100));
        let labelRevenue = (this.grossRevenue * (this.splitLabel / 100));
    
        // calculation of royalties label and artist after deduction of costs
        if (artistRevenue >= this.artistCosts) {
          this.artistBalancedRecouped = 100;
          this.artistRoyalty = artistRevenue - this.artistCosts;
        } else {
          this.artistBalancedRecouped = Math.round((artistRevenue / this.artistCosts) * 100);
          this.artistRoyalty = 0;
        }
        if (labelRevenue >= this.labelCosts) {
          this.labelRoyalty = labelRevenue - this.labelCosts;
        } else {
          this.labelRoyalty = labelRevenue - this.labelCosts;
        }
        if (this.artistCosts >= this.artistCosts - artistRevenue) {
          this.artistCosts = this.artistCosts - artistRevenue;
        }
      }

How do let I 'artistCosts' stay at 0 when it reaches 0 without popping back up to max value.

Solution

I found it after some troubleshooting, so my calculation was wrong. Still don't know why it doesn't work at the way I made it fist but this part:

if (this.artistCosts >= this.artistCosts - artistRevenue) {
          this.artistCosts = this.artistCosts - artistRevenue;
        }

I changed it to this:

   if (this.artistRoyalty > 0 ) {
      this.artistCosts = 0;
    } else {
      this.artistCosts = this.artistCosts - artistRevenue;
    }

Now this.artistCosts will stay also 0 when this.artistRoyalty goes above 0. It doesn't do a calculation anymore of multiple parameters, it just checks if the this.artistRoyalty is above 0. You can't do if (this.artistRoyalty >= 0 ) I don't know why this is, if someone can explain why the first part won't work and why if (this.artistRoyalty >= 0 ) won't work. That would be very helpfull!

Answered By - Gawkky