Some Random utility functions

randomUtils.js

function randomRange(min=0, max=100, dec=0) {
  const mag = 10 ** dec;
  return Math.floor( (Math.random() * (max - min) + min) * mag ) / mag;
}

function randomLetter(uppercase = false) {
  return String.fromCharCode(randomRange(uppercase ? 65 : 97, uppercase ? 90 : 122))
}

function randomString(minLength=8, maxLength=16) {
  return Array(randomRange(minLength, maxLength)).fill().map((_,i) => randomLetter(i === 0)).join("")
}

function randomSentence(min=8, max=32) {
  return Array(randomRange(min, max)).fill().map((_,i) => randomString(2, 18)).join(" ")
}

function randomElement(elementsArray, weightsArray) {
  let elms = Array.isArray(elementsArray) ? elementsArray : [];
  
  let weights = weightsArray;
  if (!Array.isArray(weightsArray)) {
    weights = Array(elms.length).fill(1)
  }
  
  elms = elms.map((elm, i) => {
    let qtd = parseInt(weights[i]);
    if (qtd == null || isNaN(qtd)) {
      qtd = 1;
    }
    return Array(qtd).fill(elm);
  }).flat()
  
  const idx = randomRange(0, elms.length, 0)
  return elms[idx];
}

function _testRandomFn(method, inputs=[], iterations=10**6) {
  const results = {
    min: Infinity,
    max: -Infinity,
    average: 0,
    outputs: {},
  }
  for (let i = 0; i < iterations; i += 1) {
    const val = method(...inputs);
    results.min = Math.min(val, results.min);
    results.max = Math.max(val, results.max);
    results.average += val;
    if (results.outputs[val] === undefined) {
      results.outputs[val] = {
        count: 0,
        percent: 0
      }
    }
    results.outputs[val].count += 1;
  }
  results.average = results.average / iterations
  Object.keys(results.outputs).forEach((key) => {
    results.outputs[key].percent = results.outputs[key].count / iterations
  })
  return results;
}