htmlnano
Version:
Modular HTML minifier, built on top of the PostHTML
98 lines (92 loc) • 2.78 kB
JavaScript
Object.defineProperty(exports, "__esModule", {
value: true
});
exports.default = sortAttributes;
const validOptions = new Set(['frequency', 'alphabetical']);
const processModuleOptions = options => {
if (options === true) return 'alphabetical';
return validOptions.has(options) ? options : false;
};
class AttributeTokenChain {
constructor() {
this.freqData = new Map(); // <attr, frequency>[]
}
addFromNodeAttrs(nodeAttrs) {
Object.keys(nodeAttrs).forEach(attrName => {
const attrNameLower = attrName.toLowerCase();
if (this.freqData.has(attrNameLower)) {
this.freqData.set(attrNameLower, this.freqData.get(attrNameLower) + 1);
} else {
this.freqData.set(attrNameLower, 1);
}
});
}
createSortOrder() {
let _sortOrder = [...this.freqData.entries()];
_sortOrder.sort((a, b) => b[1] - a[1]);
this.sortOrder = _sortOrder.map(i => i[0]);
}
sortFromNodeAttrs(nodeAttrs) {
const newAttrs = {};
// Convert node.attrs attrName into lower case.
const loweredNodeAttrs = {};
Object.entries(nodeAttrs).forEach(([attrName, attrValue]) => {
loweredNodeAttrs[attrName.toLowerCase()] = attrValue;
});
if (!this.sortOrder) {
this.createSortOrder();
}
this.sortOrder.forEach(attrNameLower => {
// The attrName inside "sortOrder" has been lowered
if (loweredNodeAttrs[attrNameLower] != null) {
newAttrs[attrNameLower] = loweredNodeAttrs[attrNameLower];
}
});
return newAttrs;
}
}
/** Sort attibutes */
function sortAttributes(tree, options, moduleOptions) {
const sortType = processModuleOptions(moduleOptions);
if (sortType === 'alphabetical') {
return sortAttributesInAlphabeticalOrder(tree);
}
if (sortType === 'frequency') {
return sortAttributesByFrequency(tree);
}
// Invalid configuration
return tree;
}
function sortAttributesInAlphabeticalOrder(tree) {
tree.walk(node => {
if (!node.attrs) {
return node;
}
const newAttrs = {};
Object.keys(node.attrs).sort((a, b) => typeof a.localeCompare === 'function' ? a.localeCompare(b) : a - b).forEach(attr => newAttrs[attr] = node.attrs[attr]);
node.attrs = newAttrs;
return node;
});
return tree;
}
function sortAttributesByFrequency(tree) {
const tokenchain = new AttributeTokenChain();
// Traverse through tree to get frequency
tree.walk(node => {
if (!node.attrs) {
return node;
}
tokenchain.addFromNodeAttrs(node.attrs);
return node;
});
// Traverse through tree again, this time sort the attributes
tree.walk(node => {
if (!node.attrs) {
return node;
}
node.attrs = tokenchain.sortFromNodeAttrs(node.attrs);
return node;
});
return tree;
}
;