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- var hasOwnProperty = Object.prototype.hasOwnProperty;
- var keywords = Object.create(null);
- var properties = Object.create(null);
- var HYPHENMINUS = 45; // '-'.charCodeAt()
- function isCustomProperty(str, offset) {
- offset = offset || 0;
- return str.length - offset >= 2 &&
- str.charCodeAt(offset) === HYPHENMINUS &&
- str.charCodeAt(offset + 1) === HYPHENMINUS;
- }
- function getVendorPrefix(str, offset) {
- offset = offset || 0;
- // verdor prefix should be at least 3 chars length
- if (str.length - offset >= 3) {
- // vendor prefix starts with hyper minus following non-hyper minus
- if (str.charCodeAt(offset) === HYPHENMINUS &&
- str.charCodeAt(offset + 1) !== HYPHENMINUS) {
- // vendor prefix should contain a hyper minus at the ending
- var secondDashIndex = str.indexOf('-', offset + 2);
- if (secondDashIndex !== -1) {
- return str.substring(offset, secondDashIndex + 1);
- }
- }
- }
- return '';
- }
- function getKeywordDescriptor(keyword) {
- if (hasOwnProperty.call(keywords, keyword)) {
- return keywords[keyword];
- }
- var name = keyword.toLowerCase();
- if (hasOwnProperty.call(keywords, name)) {
- return keywords[keyword] = keywords[name];
- }
- var custom = isCustomProperty(name, 0);
- var vendor = !custom ? getVendorPrefix(name, 0) : '';
- return keywords[keyword] = Object.freeze({
- basename: name.substr(vendor.length),
- name: name,
- vendor: vendor,
- prefix: vendor,
- custom: custom
- });
- }
- function getPropertyDescriptor(property) {
- if (hasOwnProperty.call(properties, property)) {
- return properties[property];
- }
- var name = property;
- var hack = property[0];
- if (hack === '/') {
- hack = property[1] === '/' ? '//' : '/';
- } else if (hack !== '_' &&
- hack !== '*' &&
- hack !== '$' &&
- hack !== '#' &&
- hack !== '+' &&
- hack !== '&') {
- hack = '';
- }
- var custom = isCustomProperty(name, hack.length);
- // re-use result when possible (the same as for lower case)
- if (!custom) {
- name = name.toLowerCase();
- if (hasOwnProperty.call(properties, name)) {
- return properties[property] = properties[name];
- }
- }
- var vendor = !custom ? getVendorPrefix(name, hack.length) : '';
- var prefix = name.substr(0, hack.length + vendor.length);
- return properties[property] = Object.freeze({
- basename: name.substr(prefix.length),
- name: name.substr(hack.length),
- hack: hack,
- vendor: vendor,
- prefix: prefix,
- custom: custom
- });
- }
- module.exports = {
- keyword: getKeywordDescriptor,
- property: getPropertyDescriptor,
- isCustomProperty: isCustomProperty,
- vendorPrefix: getVendorPrefix
- };
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