scancss/dist/handlers/properties/handlePerformanceHacks/index.js

A robust CSS stylesheet statistics collector and analyzer

'use strict';

Object.defineProperty(exports, "__esModule", {
	value: true
});
exports.handlePerformanceHacks = handlePerformanceHacks;

var _postcssValuesParser = require('postcss-values-parser');

var _postcssValuesParser2 = _interopRequireDefault(_postcssValuesParser);

var _countUsage = require('../../../calculators/countUsage');

var _isSafeAst = require('../../../predicates/isSafeAst');

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

const reTranslate3dHack = /translate3d\(\s*0\s*,\s*0\s*,\s*0\s*\)/i;
const reTranslateZHack = /translateZ\(\s*0\s*\)/i;
const reRotateZHack = /rotateZ\(\s*(360deg|400grad|1turn|6\.2832rad)\s*\)/i;

function walkNodes(nodes, decl, report) {
	nodes.forEach(node => {
		/* istanbul ignore else */
		if (node.type === 'func') {
			const wholeFunc = String(node);
			const wholeDecl = String(decl);

			if (reTranslate3dHack.test(wholeFunc)) {
				(0, _countUsage.countUsage)(wholeDecl, report.properties.performanceHacks);
			}

			if (reTranslateZHack.test(wholeFunc)) {
				(0, _countUsage.countUsage)(wholeDecl, report.properties.performanceHacks);
			}

			if (reRotateZHack.test(wholeFunc)) {
				(0, _countUsage.countUsage)(wholeDecl, report.properties.performanceHacks);
			}
		}
	});
}

function handlePerformanceHacks(decl, report) {
	if (decl.prop.endsWith('transform')) {
		try {
			const ast = (0, _postcssValuesParser2.default)(decl.value).parse();

			/* istanbul ignore else */
			if ((0, _isSafeAst.isSafeAst)(ast)) {
				walkNodes(ast.nodes[0].nodes, decl, report);
			}
		} catch (err) {
			/* istanbul ignore next */
			/* eslint-disable-next-line no-console */
			console.log(`'postcss-values-parser' module error\n${err}`);
		}
	}

	if (decl.prop === 'will-change') {
		(0, _countUsage.countUsage)(String(decl), report.properties.performanceHacks);
	} else if (decl.prop === 'contain' && decl.value.trim() !== 'none') {
		(0, _countUsage.countUsage)(String(decl), report.properties.performanceHacks);
	}
}