Two new media queries related rules

lib/tools/mediaQueriesChecker.js

@@ -0,0 +1,168 @@
+var debug   = require('debug')('ylt:mediaQueriesChecker');
+var parseMediaQuery = require('css-mq-parser');
+var offendersHelpers = require('../offendersHelpers');
+
+
+var mediaQueriesChecker = function() {
+    'use strict';
+
+    var MOBILE_MIN_BREAKPOINT = 200;
+    var MOBILE_MAX_BREAKPOINT = 300;
+
+    this.analyzeMediaQueries = function(data) {
+        debug('Starting to check all media queries...');
+
+        var offenders = data.toolsResults.phantomas.offenders.cssMediaQueries;
+        var mediaQueries = (offenders) ? this.parseAllMediaQueries(offenders) : [];
+        
+        var notMobileFirstCount = 0;
+        var notMobileFirstOffenders = [];
+
+        var breakpointsOffenders = {};
+
+        for (var i = 0; i < mediaQueries.length; i++) {
+            var item = mediaQueries[i];
+
+            if (!item) {
+                continue;
+            }
+
+            if (item.isForMobile) {
+                notMobileFirstCount += item.mediaQuery.rules;
+                notMobileFirstOffenders.push(item.mediaQuery);
+            }
+
+            for (var j = 0; j < item.breakpoints.length; j++) {
+                var breakpointString = item.breakpoints[j].string;
+                if (!breakpointsOffenders[breakpointString]) {
+                    breakpointsOffenders[breakpointString] = {
+                        count: 1,
+                        pixels: item.breakpoints[j].pixels
+                    };
+                } else {
+                    breakpointsOffenders[breakpointString].count += 1;
+                }
+            }
+        }
+
+        data.toolsResults.mediaQueriesChecker = {
+            metrics: {
+                cssMobileFirst: notMobileFirstCount,
+                cssBreakpoints: Object.keys(breakpointsOffenders).length
+            },
+            offenders: {
+                cssMobileFirst: notMobileFirstOffenders,
+                cssBreakpoints: breakpointsOffenders
+            }
+        };
+
+        debug('End of media queries check');
+
+        return data;
+    };
+
+    this.parseAllMediaQueries = function(offenders) {
+        return offenders.map(this.parseOneMediaQuery);
+    };
+
+    this.parseOneMediaQuery = function(offender) {
+        var splittedOffender = offendersHelpers.cssOffenderPattern(offender);
+        var parts = /^@media (.*) \((\d+ rules)\)$/.exec(splittedOffender.css);
+
+        if (!parts) {
+            debug('Failed to parse media query ' + offender);
+            return false;
+        }
+
+        var rulesCount = parseInt(parts[2], 10);
+        var query = parts[1];
+
+        var isForMobile = false;
+        var breakpoints = [];
+
+        try {
+
+            var ast = parseMediaQuery(query);
+
+            var min = 0;
+            var max = Infinity;
+            var pixels;
+
+            ast.forEach(function(astItem) {
+                astItem.expressions.forEach(function(expression) {
+                    if (expression.feature === 'width' || expression.feature === 'device-width') {
+                        if (astItem.inverse === false) {
+                            if (expression.modifier === 'max') {
+                                pixels = toPixels(expression.value);
+                                max = Math.min(max, pixels);
+                                breakpoints.push({
+                                    string: expression.value,
+                                    pixels: pixels
+                                });
+                            } else if (expression.modifier === 'min') {
+                                pixels = toPixels(expression.value);
+                                min = Math.max(min, pixels);
+                                breakpoints.push({
+                                    string: expression.value,
+                                    pixels: pixels
+                                });
+                            }
+                        } else if (astItem.inverse === true) {
+                            if (expression.modifier === 'max') {
+                                pixels = toPixels(expression.value);
+                                min = Math.max(min, pixels);
+                                breakpoints.push({
+                                    string: expression.value,
+                                    pixels: pixels
+                                });
+                            } else if (expression.modifier === 'min') {
+                                pixels = toPixels(expression.value);
+                                max = Math.min(max, pixels);
+                                breakpoints.push({
+                                    string: expression.value,
+                                    pixels: pixels
+                                });
+                            }
+                        }
+                    }
+                });
+            });
+
+            isForMobile = (min <= MOBILE_MIN_BREAKPOINT && max >= MOBILE_MAX_BREAKPOINT && max !== Infinity);
+
+        } catch(error) {
+            debug('Failed to parse media query ' + offender);
+        }
+
+        return {
+            mediaQuery: {
+                query: query,
+                rules: rulesCount,
+                file: splittedOffender.file,
+                line: splittedOffender.line,
+                column: splittedOffender.column
+            },
+            isForMobile: isForMobile,
+            breakpoints: breakpoints
+        };
+    };
+
+    // Parses a size in em, pt (or px) and returns it in px
+    function toPixels(size) {
+        var splittedSize = /^([\d\.]+)(.*)/.exec(size);
+        var value = parseFloat(splittedSize[1]);
+        var unit = splittedSize[2];
+
+        if (unit === 'em') {
+            return value * 16;
+        }
+
+        if (unit === 'pt') {
+            return value / 12 * 16;
+        }
+
+        return value;
+    }
+};
+
+module.exports = new mediaQueriesChecker();