SVG path d attribute derelative

derelative.js

function derelativePathD(d,fixed){ 
  let steps = d
          .replace(/[,\s]+/g,' ')
      .replace(/-\./g,'-0.')
      .replace(/(?<=\.\d+)\./g,' 0.')
      .split(/([MmLlAaCcSsQqTtVvHhZz])/g)
      .splice(1)
      .map((v,i) => !(i%2) ? v : v
         .split(/\s+/g)
         .map(v=>v.split(/(-?[\d]*(?:\.\d+)?(?:e-?\d{1,2})?)/g)
                .filter(Boolean))
         .flat(1)
         .map(v=>parseFloat(v))
      );

  let x,y,output=[];
  for(let i=0;i<steps.length;i+=2){ 
    let mode = steps[i], p = steps[i+1]; 
    if(mode=="Z"||mode=="z") { 
      output.push(mode);
    }
    if(mode=="M"){ 
       x=p.shift(); 
       y=p.shift(); 
       output.push('M',x.toFixed(fixed),y.toFixed(fixed)); 
       mode='L'; 
    }
    if(mode=='m'){ 
       x+=p.shift(); 
       y+=p.shift(); 
       output.push('M',x.toFixed(fixed),y.toFixed(fixed)); 
       mode='l'; 
    }
    if(mode=='L'){ 
       while(p.length) { 
         x=p.shift(); 
         y=p.shift(); 
         output.push('L',x.toFixed(fixed),y.toFixed(fixed)); 
       } 
    }
    if(mode=='l'){ 
       while(p.length) { 
         x+=p.shift(); 
         y+=p.shift(); 
         output.push('L',x.toFixed(fixed),y.toFixed(fixed)); 
      } 
    }
    if(mode=='S'){ 
      while(p.length) { 
        let x2, y2; 
        x2=p.shift(); 
        y2=p.shift(); 
        x=p.shift(); 
        y=p.shift(); 
        output.push('S',x2.toFixed(fixed),y2.toFixed(fixed),x.toFixed(fixed),y.toFixed(fixed)); 
      } 
    }
    if(mode=='s'){ 
      while(p.length) { 
        let x2=x, y2=y; 
        x2+=p.shift(); 
        y2+=p.shift(); 
        x+=p.shift(); 
        y+=p.shift(); 
        output.push('S',x2.toFixed(fixed),y2.toFixed(fixed),x.toFixed(fixed),y.toFixed(fixed)); 
      } 
    }
    if(mode=='C'){ 
      while(p.length) { 
        let x1,x2,y1,y2; 
        x1=p.shift(); 
        y1=p.shift(); 
        x2=p.shift(); 
        y2=p.shift(); 
        x=p.shift(); 
        y=p.shift(); 
        output.push('C',x1.toFixed(fixed),y1.toFixed(fixed),x2.toFixed(fixed),y2.toFixed(fixed),x.toFixed(fixed),y.toFixed(fixed)); 
      } 
    }
    if(mode=='c'){ 
      while(p.length) { 
        let x1=x,x2=x,y1=y,y2=y; 
        x1+=p.shift(); 
        y1+=p.shift(); 
        x2+=p.shift(); 
        y2+=p.shift(); 
        x+=p.shift(); 
        y+=p.shift(); 
        output.push('C',x1.toFixed(fixed),y1.toFixed(fixed),x2.toFixed(fixed),y2.toFixed(fixed),x.toFixed(fixed),y.toFixed(fixed)); 
      } 
    }

    if(mode=='Q'){
      while(p.length) { 
        let x1, y1; 
        x1=p.shift(); 
        y1=p.shift(); 
        x=p.shift(); 
        y=p.shift(); 
        output.push('Q',x1.toFixed(fixed),y1.toFixed(fixed),x.toFixed(fixed),y.toFixed(fixed)); 
      } 
    }
    if(mode=='q'){
      while(p.length) { 
        let x1=x, y1=y; 
        x1+=p.shift(); 
        y1+=p.shift(); 
        x+=p.shift(); 
        y+=p.shift(); 
        output.push('Q',x1.toFixed(fixed),y1.toFixed(fixed),x.toFixed(fixed),y.toFixed(fixed)); 
      } 
    }
    if(mode=='T'){
      while(p.length) { 
        x=p.shift(); 
        y=p.shift(); 
        output.push('T',x.toFixed(fixed),y.toFixed(fixed)); 
      } 
    }
    if(mode=='t'){
      while(p.length) { 
        x+=p.shift(); 
        y+=p.shift(); 
        output.push('T',x.toFixed(fixed),y.toFixed(fixed)); 
      } 
    }
    if(mode=='A'){
      while(p.length) { 
        let rx=p.shift(); 
        let ry=p.shift(); 
        let a=p.shift(); 
        let lf=p.shift(); 
        let sf=p.shift(); 
        x=p.shift(); 
        y=p.shift(); 
        output.push('A',rx.toFixed(fixed),ry.toFixed(fixed),a.toFixed(fixed),lf,sf,x.toFixed(fixed),y.toFixed(fixed)); 
      } 
    }
    if(mode=='a'){
      while(p.length) { 
        let rx=p.shift(); 
        let ry=p.shift(); 
        let a=p.shift(); 
        let lf=p.shift(); 
        let sf=p.shift(); 
        x+=p.shift(); 
        y+=p.shift(); 
        output.push('A',rx.toFixed(fixed),ry.toFixed(fixed),a.toFixed(fixed),lf,sf,x.toFixed(fixed),y.toFixed(fixed)); 
      } 
    }
    if(mode=='v'){
      while(p.length) { 
        y+=p.shift(); 
        output.push('V',y.toFixed(fixed)); 
      } 
    }
    if(mode=='V'){
      while(p.length) { 
        y=p.shift(); 
        output.push('V',y.toFixed(fixed)); 
      } 
    }
    if(mode=='h'){
      while(p.length) { 
        x+=p.shift(); 
        output.push('H',x.toFixed(fixed)); 
      } 
    }
    if(mode=='H'){
      while(p.length) { 
        x=p.shift(); 
        output.push('H',x.toFixed(fixed)); 
      } 
    }
  }
  return output.join` `;
}