bigNumberFormat.js

/**
  * Nicely format large numbers to make them readable:
  * Billions to one decimal like "$1.3 billion"
  * Millions to nearest million like "$346 million"
  * Thousands to nearest thousand like "$144,000"
  * @param {number} The number to format
  * @returns {string} Readable string with dollar sign and amount
  */
function niceBigNumber(num) {
  // format billions to one decimal like "$1.3 billion"
  if (Math.abs(Number(num)) >= 1.0e+9) {
    var float = Math.abs(Number(num)) / 1.0e+9;
    num = '$' + float.toFixed(1) + ' billion';
  } 
  // format millions to nearest million like "$346 million"
  else if (Math.abs(Number(num)) >= 1.0e+6) {
    var float = Math.abs(Number(num)) / 1.0e+6;   
    num = '$' + float.toFixed() + ' million';
  } 
  // format thousands to nearest thousand like "$144,000"
  else if (Math.abs(Number(num)) >= 1.0e+3) {
    num = '$' + (Math.round(1000*num)/1000).toLocaleString();
  }
  return num;
}