1  'use strict';
 2  
 3  var has = require('has');
 4  
 5  function specifierIncluded(current, specifier) {
 6  	var nodeParts = current.split('.');
 7  	var parts = specifier.split(' ');
 8  	var op = parts.length > 1 ? parts[0] : '=';
 9  	var versionParts = (parts.length > 1 ? parts[1] : parts[0]).split('.');
10  
11  	for (var i = 0; i < 3; ++i) {
12  		var cur = parseInt(nodeParts[i] || 0, 10);
13  		var ver = parseInt(versionParts[i] || 0, 10);
14  		if (cur === ver) {
15  			continue; // eslint-disable-line no-restricted-syntax, no-continue
16  		}
17  		if (op === '<') {
18  			return cur < ver;
19  		}
20  		if (op === '>=') {
21  			return cur >= ver;
22  		}
23  		return false;
24  	}
25  	return op === '>=';
26  }
27  
28  function matchesRange(current, range) {
29  	var specifiers = range.split(/ ?&& ?/);
30  	if (specifiers.length === 0) {
31  		return false;
32  	}
33  	for (var i = 0; i < specifiers.length; ++i) {
34  		if (!specifierIncluded(current, specifiers[i])) {
35  			return false;
36  		}
37  	}
38  	return true;
39  }
40  
41  function versionIncluded(nodeVersion, specifierValue) {
42  	if (typeof specifierValue === 'boolean') {
43  		return specifierValue;
44  	}
45  
46  	var current = typeof nodeVersion === 'undefined'
47  		? process.versions && process.versions.node
48  		: nodeVersion;
49  
50  	if (typeof current !== 'string') {
51  		throw new TypeError(typeof nodeVersion === 'undefined' ? 'Unable to determine current node version' : 'If provided, a valid node version is required');
52  	}
53  
54  	if (specifierValue && typeof specifierValue === 'object') {
55  		for (var i = 0; i < specifierValue.length; ++i) {
56  			if (matchesRange(current, specifierValue[i])) {
57  				return true;
58  			}
59  		}
60  		return false;
61  	}
62  	return matchesRange(current, specifierValue);
63  }
64  
65  var data = require('./core.json');
66  
67  module.exports = function isCore(x, nodeVersion) {
68  	return has(data, x) && versionIncluded(nodeVersion, data[x]);
69  };