index.js

var semver = require('semver-utils');
var fs     = require('fs');


/**
  * Bump semantic version (SemVer) number in VERSION according to MASKS. MASKS
  * is an array composed of three digits, e.g. [0, 1, 0]. The topmost
  * (left-most) nonzero bit of SemVer number is bumped (incremented) and the
  * lower bits are set to zeros.
  * @class SemverIncrement
  */

 /**
  * Call this function directly by requiring in Node.js runtime.
  *
  * @method main
  * @param {Array} masks
  * @param {String} version
  * @return {String}
  */ 
module.exports = function (masks, version) {
  "use strict";

  if (typeof masks === 'string') {
    version = masks;
    masks = [0, 0, 0];
  }

  let bitMap = ['major', 'minor', 'patch'];
  let bumpAt = 'patch';
  let oldVer = version.match(/\d+/g);

  for (let i = 0; i < masks.length; ++i) {
    if (masks[i] === 1) {
      bumpAt = bitMap[i];
      break;
    }
  }

  let bumpIdx = bitMap.indexOf(bumpAt);
  let newVersion = []
  for (let i = 0; i < oldVer.length; ++i) {
    if (i < bumpIdx) {
      newVersion[i] = +oldVer[i];
    } else if (i === bumpIdx) {
      newVersion[i] = +oldVer[i] + 1;
    } else {
      newVersion[i] = 0;
    }
  }

  return newVersion.join('.');
};