understanding-graphs/src/js/utilities/formatter.js

// Formatter for number representations
import round from './math';

// get a fixed number of digits
const fixedDigits = (number, numberDigits) => {
  const str = `${number}`;
  let padding = '';

  for (let i = 0; i < numberDigits; i += 1) {
    padding += '0';
  }

  return padding.substring(0, padding.length - str.length) + str;
};

const needsSpacing = (val1, val2) => {
  let toBeSpaced = 0;

  // Add additional spacing when one value has decimal places and the other not
  if ((val1 < 1 && val2 >= 1) || (val1 >= 1 && val2 < 1)) {
    toBeSpaced = 1;
  }

  return toBeSpaced;
};

// - 0 <= x < 1:        1 decimal place
// - 1 <= x <= 100.000: 0 decimal places
const getPrecision = (val) => {
  if (val < 1) {
    return 10;
  }
  return 1;
};

// - 0 <= x < 1:        0 spaces
// - 1 <= x <= 100.000: 2 spaces
const getSpacing = (val) => {
  if (val >= 1) {
    return 2;
  }
  return 0;
};

// - 0 <= x < 1:        1 decimal place
// - 1 <= x <= 100.000: 0 decimal places
const getFormattedValue = (val) => {

  const digits = Math.log(val) / Math.log(10);
  let formattedValue;

  if (digits < 0) {
    formattedValue = Math.max(round(val, 1), 0.1);
  } else {
    formattedValue = round(val, 0);
  }

  return formattedValue;
};

const haveSameRepresentation = (value1, value2) => {

  const p1 = getFormattedValue(value1);
  const p2 = getFormattedValue(value2);

  return p1 === p2 || (p1 < 0.1 && p2 < 0.1);
};

export {
  fixedDigits,
  needsSpacing,
  getPrecision,
  getSpacing,
  getFormattedValue,
  haveSameRepresentation
};