scancss/dist/handlers/handleUnits/index.js

A robust CSS stylesheet statistics collector and analyzer

'use strict';

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

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

var _postcssValuesParser2 = _interopRequireDefault(_postcssValuesParser);

var _cssUnits = require('../../constants/cssUnits');

var _cssUnitsThatAllowZeroWithoutUnit = require('../../constants/cssUnitsThatAllowZeroWithoutUnit');

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

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

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

function walkNodes(nodes, decl, report, options) {
	nodes.forEach(node => {
		if (node.type === 'number' && node.unit !== '') {
			const unit = node.unit.toLowerCase();
			const valueWithUnit = node.value + unit;

			report.units.total++;
			(0, _countUsage.countUsage)(unit, report.units.usage);

			if (_cssUnits.cssUnits.includes(unit)) {
				/** Count negative margins */
				if (decl.prop.startsWith('margin') && node.value.startsWith('-') && options.properties) {
					report.properties.negativeMargins++;
				}

				/** Count excessive units, i.e. `0px` */
				if (parseFloat(node.value) === 0 && _cssUnitsThatAllowZeroWithoutUnit.cssUnitsThatAllowZeroWithoutUnit.includes(unit)) {
					report.units.excessive.total++;
					(0, _countUsage.countUsage)(valueWithUnit, report.units.excessive.usage);
				}
			} else {
				report.units.unknown.total++;
				(0, _countUsage.countUsage)(unit, report.units.unknown.usage);
			}
		}

		/* istanbul ignore else */
		if (node.type === 'func' && Array.isArray(node.nodes)) {
			walkNodes(node.nodes, decl, report, options);
		}
	});
}

function handleUnits(decl, report, options) {
	const currentUnitsTotal = report.units.total;

	try {
		const ast = (0, _postcssValuesParser2.default)(decl.value).parse();

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

	if (currentUnitsTotal === report.units.total && options.properties) {
		report.properties.unitless++;
	}
}