R lm() poly output to JS function

gistfile1.txt

var coeff = [
  [1,0],
  [2,0],
  [3,0],
  [4,0],
  [0,1],
  [1,1],
  [2,1],
  [3,1],
  [0,2],
  [1,2],
  [2,2],
  [0,3],
  [1,3],
  [0,4],
]


function toFormula(arr, i) {
  return  'y[' + (i + 1) + '] * ' + arr.map((val,i) => {
    let variable = 'size'
    if (i === 1) variable = 'distance'
    if (val === 1) return variable
    if (val > 1) return 'Math.pow(' + variable + ',' + val + ')'
  }).filter(a => a !== undefined).join(' * ')
}

;(() => {
 return `function runRegression(y,size,distance) {
   return ${'y[0]\n + ' + coeff.map(toFormula).join('\n + ')}
 }`
})()