utils.js

'use strict';

var splitString = require('split-string');
var utils = module.exports;

/**
 * Module dependencies
 */

utils.extend = require('extend-shallow');
utils.flatten = require('arr-flatten');
utils.isObject = require('isobject');
utils.fillRange = require('fill-range');
utils.repeat = require('repeat-element');
utils.unique = require('array-unique');

utils.define = function(obj, key, val) {
  Object.defineProperty(obj, key, {
    writable: true,
    configurable: true,
    enumerable: false,
    value: val
  });
};

/**
 * Returns true if the given string contains only empty brace sets.
 */

utils.isEmptySets = function(str) {
  return /^(?:\{,\})+$/.test(str);
};

/**
 * Returns true if the given string contains only empty brace sets.
 */

utils.isQuotedString = function(str) {
  var open = str.charAt(0);
  if (open === '\'' || open === '"' || open === '`') {
    return str.slice(-1) === open;
  }
  return false;
};

/**
 * Create the key to use for memoization. The unique key is generated
 * by iterating over the options and concatenating key-value pairs
 * to the pattern string.
 */

utils.createKey = function(pattern, options) {
  var id = pattern;
  if (typeof options === 'undefined') {
    return id;
  }
  var keys = Object.keys(options);
  for (var i = 0; i < keys.length; i++) {
    var key = keys[i];
    id += ';' + key + '=' + String(options[key]);
  }
  return id;
};

/**
 * Normalize options
 */

utils.createOptions = function(options) {
  var opts = utils.extend.apply(null, arguments);
  if (typeof opts.expand === 'boolean') {
    opts.optimize = !opts.expand;
  }
  if (typeof opts.optimize === 'boolean') {
    opts.expand = !opts.optimize;
  }
  if (opts.optimize === true) {
    opts.makeRe = true;
  }
  return opts;
};

/**
 * Join patterns in `a` to patterns in `b`
 */

utils.join = function(a, b, options) {
  options = options || {};
  a = utils.arrayify(a);
  b = utils.arrayify(b);

  if (!a.length) return b;
  if (!b.length) return a;

  var len = a.length;
  var idx = -1;
  var arr = [];

  while (++idx < len) {
    var val = a[idx];
    if (Array.isArray(val)) {
      for (var i = 0; i < val.length; i++) {
        val[i] = utils.join(val[i], b, options);
      }
      arr.push(val);
      continue;
    }

    for (var j = 0; j < b.length; j++) {
      var bval = b[j];

      if (Array.isArray(bval)) {
        arr.push(utils.join(val, bval, options));
      } else {
        arr.push(val + bval);
      }
    }
  }
  return arr;
};

/**
 * Split the given string on `,` if not escaped.
 */

utils.split = function(str, options) {
  var opts = utils.extend({sep: ','}, options);
  if (typeof opts.keepQuotes !== 'boolean') {
    opts.keepQuotes = true;
  }
  if (opts.unescape === false) {
    opts.keepEscaping = true;
  }
  return splitString(str, opts, utils.escapeBrackets(opts));
};

/**
 * Expand ranges or sets in the given `pattern`.
 *
 * @param {String} `str`
 * @param {Object} `options`
 * @return {Object}
 */

utils.expand = function(str, options) {
  var opts = utils.extend({rangeLimit: 10000}, options);
  var segs = utils.split(str, opts);
  var tok = { segs: segs };

  if (utils.isQuotedString(str)) {
    return tok;
  }

  if (opts.rangeLimit === true) {
    opts.rangeLimit = 10000;
  }

  if (segs.length > 1) {
    if (opts.optimize === false) {
      tok.val = segs[0];
      return tok;
    }

    tok.segs = utils.stringifyArray(tok.segs);
  } else if (segs.length === 1) {
    var arr = str.split('..');

    if (arr.length === 1) {
      tok.val = tok.segs[tok.segs.length - 1] || tok.val || str;
      tok.segs = [];
      return tok;
    }

    if (arr.length === 2 && arr[0] === arr[1]) {
      tok.escaped = true;
      tok.val = arr[0];
      tok.segs = [];
      return tok;
    }

    if (arr.length > 1) {
      if (opts.optimize !== false) {
        opts.optimize = true;
        delete opts.expand;
      }

      if (opts.optimize !== true) {
        var min = Math.min(arr[0], arr[1]);
        var max = Math.max(arr[0], arr[1]);
        var step = arr[2] || 1;

        if (opts.rangeLimit !== false && ((max - min) / step >= opts.rangeLimit)) {
          throw new RangeError('expanded array length exceeds range limit. Use options.rangeLimit to increase or disable the limit.');
        }
      }

      arr.push(opts);
      tok.segs = utils.fillRange.apply(null, arr);

      if (!tok.segs.length) {
        tok.escaped = true;
        tok.val = str;
        return tok;
      }

      if (opts.optimize === true) {
        tok.segs = utils.stringifyArray(tok.segs);
      }

      if (tok.segs === '') {
        tok.val = str;
      } else {
        tok.val = tok.segs[0];
      }
      return tok;
    }
  } else {
    tok.val = str;
  }
  return tok;
};

/**
 * Ensure commas inside brackets and parens are not split.
 * @param {Object} `tok` Token from the `split-string` module
 * @return {undefined}
 */

utils.escapeBrackets = function(options) {
  return function(tok) {
    if (tok.escaped && tok.val === 'b') {
      tok.val = '\\b';
      return;
    }

    if (tok.val !== '(' && tok.val !== '[') return;
    var opts = utils.extend({}, options);
    var brackets = [];
    var parens = [];
    var stack = [];
    var val = tok.val;
    var str = tok.str;
    var i = tok.idx - 1;

    while (++i < str.length) {
      var ch = str[i];

      if (ch === '\\') {
        val += (opts.keepEscaping === false ? '' : ch) + str[++i];
        continue;
      }

      if (ch === '(') {
        parens.push(ch);
        stack.push(ch);
      }

      if (ch === '[') {
        brackets.push(ch);
        stack.push(ch);
      }

      if (ch === ')') {
        parens.pop();
        stack.pop();
        if (!stack.length) {
          val += ch;
          break;
        }
      }

      if (ch === ']') {
        brackets.pop();
        stack.pop();
        if (!stack.length) {
          val += ch;
          break;
        }
      }
      val += ch;
    }

    tok.split = false;
    tok.val = val.slice(1);
    tok.idx = i;
  };
};

/**
 * Returns true if the given string looks like a regex quantifier
 * @return {Boolean}
 */

utils.isQuantifier = function(str) {
  return /^(?:[0-9]?,[0-9]|[0-9],)$/.test(str);
};

/**
 * Cast `val` to an array.
 * @param {*} `val`
 */

utils.stringifyArray = function(arr) {
  return [utils.arrayify(arr).join('|')];
};

/**
 * Cast `val` to an array.
 * @param {*} `val`
 */

utils.arrayify = function(arr) {
  if (typeof arr === 'undefined') {
    return [];
  }
  if (typeof arr === 'string') {
    return [arr];
  }
  return arr;
};

/**
 * Returns true if the given `str` is a non-empty string
 * @return {Boolean}
 */

utils.isString = function(str) {
  return str != null && typeof str === 'string';
};

/**
 * Get the last element from `array`
 * @param {Array} `array`
 * @return {*}
 */

utils.last = function(arr, n) {
  return arr[arr.length - (n || 1)];
};

utils.escapeRegex = function(str) {
  return str.replace(/\\?([!^*?()[\]{}+?/])/g, '\\$1');
};