lib/rules/no-unused-styles.js
/**
* @fileoverview Detects unused styles
* @author Tom Hastjarjanto
*/
'use strict';
const Components = require('../util/Components');
const styleSheet = require('../util/stylesheet');
const { StyleSheets } = styleSheet;
const { astHelpers } = styleSheet;
const create = Components.detect((context, components) => {
const styleSheets = new StyleSheets();
const styleReferences = new Set();
function reportUnusedStyles(unusedStyles) {
Object.keys(unusedStyles).forEach((key) => {
if ({}.hasOwnProperty.call(unusedStyles, key)) {
const styles = unusedStyles[key];
styles.forEach((node) => {
const message = [
'Unused style detected: ',
key,
'.',
node.key.name,
].join('');
context.report(node, message);
});
}
});
}
return {
MemberExpression: function (node) {
const styleRef = astHelpers.getPotentialStyleReferenceFromMemberExpression(node);
if (styleRef) {
styleReferences.add(styleRef);
}
},
CallExpression: function (node) {
if (astHelpers.isStyleSheetDeclaration(node, context.settings)) {
const styleSheetName = astHelpers.getStyleSheetName(node);
const styles = astHelpers.getStyleDeclarations(node);
styleSheets.add(styleSheetName, styles);
}
},
'Program:exit': function () {
const list = components.all();
if (Object.keys(list).length > 0) {
styleReferences.forEach((reference) => {
styleSheets.markAsUsed(reference);
});
reportUnusedStyles(styleSheets.getUnusedReferences());
}
},
};
});
module.exports = {
meta: {
schema: [],
},
create,
};