plugins/cleanupIDs: renamed from removeUnusedIDs; minify used IDs (fix #7)

plugins/cleanupIDs.js

@@ -0,0 +1,194 @@
+'use strict';
+
+var referencesProps = require('./_collections').referencesProps,
+    regReferencesUrl = /^url\(#(.+?)\)$/,
+    regReferencesHref = /^#(.+?)$/,
+    styleOrScript = ['style', 'script'],
+    generateIDchars = [
+        'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
+        'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'
+    ],
+    maxIDindex = generateIDchars.length - 1;
+
+/**
+ * Remove unused and minify used IDs
+ * (only if there are no any <style> or <script>).
+ *
+ * @param {Object} item current iteration item
+ * @param {Object} params plugin params
+ *
+ * @author Kir Belevich
+ */
+exports.cleanupIDs = function(data, params) {
+
+    var currentID,
+        currentIDstring,
+        IDs = {},
+        referencesIDs = {},
+        hasStyleOrScript = false;
+
+    /**
+     * Bananas!
+     *
+     * @param {Array} items input items
+     * @return {Array} output items
+     */
+    function monkeys(items) {
+
+        var i = 0,
+            length = items.content.length;
+
+        while(i < length) {
+
+            var item = items.content[i],
+                match;
+
+            // check if <style> of <script> presents
+            if (item.isElem(styleOrScript)) {
+                hasStyleOrScript = true;
+            }
+
+            // …and don't remove any ID if yes
+            if (!hasStyleOrScript) {
+
+                if (item.isElem()) {
+
+                    item.eachAttr(function(attr) {
+                        // save IDs
+                        if (attr.name === 'id') {
+                            IDs[item.attr('id').value] = item;
+                        }
+
+                        // save IDs url() references
+                        else if (referencesProps.indexOf(attr.name) > -1) {
+                            match = attr.value.match(regReferencesUrl);
+
+                            if (match) {
+                                if (referencesIDs[match[1]]) {
+                                    referencesIDs[match[1]].push(attr);
+                                } else {
+                                    referencesIDs[match[1]] = [attr];
+                                }
+                            }
+                        }
+
+                        // save IDs href references
+                        else if (attr.name === 'xlink:href') {
+                            match = attr.value.match(regReferencesHref);
+
+                            if (match) {
+                                if (referencesIDs[match[1]]) {
+                                    referencesIDs[match[1]].push(attr);
+                                } else {
+                                    referencesIDs[match[1]] = [attr];
+                                }
+                            }
+                        }
+                    });
+
+                }
+
+                // go deeper
+                if (item.content) {
+                    monkeys(item);
+                }
+
+            }
+
+            i++;
+
+        }
+
+        return items;
+
+    }
+
+    data = monkeys(data);
+
+    if (!hasStyleOrScript) {
+
+
+        for (var k in referencesIDs) {
+            if (IDs[k]) {
+
+                // replace referenced IDs with the minified ones
+                if (params.minify) {
+
+                    currentIDstring = getIDstring(currentID = generateID(currentID));
+                    IDs[k].attr('id').value = currentIDstring;
+
+                    referencesIDs[k].forEach(function(attr) {
+                        attr.value = attr.value.replace('#' + k, '#' + currentIDstring);
+                    });
+
+                }
+
+                // don't remove referenced IDs
+                delete IDs[k];
+
+            }
+        }
+
+        // remove non-referenced IDs attributes from elements
+        if (params.remove) {
+
+            for(var ID in IDs) {
+                IDs[ID].removeAttr('id');
+            }
+
+        }
+
+    }
+
+    return data;
+
+};
+
+/**
+ * Generate unique minimal ID.
+ *
+ * @param {Array} [currentID] current ID
+ * @return {Array} generated ID array
+ */
+function generateID(currentID) {
+
+    if (!currentID) return [0];
+
+    currentID[currentID.length - 1]++;
+
+    for(var i = currentID.length - 1; i > 0; i--) {
+        if (currentID[i] > maxIDindex) {
+            currentID[i] = 0;
+
+            if (currentID[i - 1] !== undefined) {
+                currentID[i - 1]++;
+            }
+        }
+    }
+
+    if (currentID[0] > maxIDindex) {
+        currentID[0] = 0;
+        currentID.unshift(0);
+    }
+
+    return currentID;
+
+}
+
+/**
+ * Get string from generated ID array.
+ *
+ * @param {Array} arr input ID array
+ * @return {String} output ID string
+ */
+function getIDstring(arr) {
+
+    var str = '';
+
+    arr.forEach(function(i) {
+        str += generateIDchars[i];
+    });
+
+    return str;
+
+}