eslint-plugin-svelte
Version:
ESLint plugin for Svelte using AST
90 lines (89 loc) • 3.46 kB
JavaScript
import { createRule } from '../utils/index.js';
import { parseStyleAttributeValue } from '../utils/css-utils/index.js';
export default createRule('no-dupe-style-properties', {
meta: {
docs: {
description: 'disallow duplicate style properties',
category: 'Possible Errors',
recommended: true
},
schema: [],
messages: {
unexpected: "Duplicate property '{{name}}'."
},
type: 'problem'
},
create(context) {
return {
SvelteStartTag(node) {
const reported = new Set();
const beforeDeclarations = new Map();
for (const { decls } of iterateStyleDeclSetFromAttrs(node.attributes)) {
for (const decl of decls) {
const already = beforeDeclarations.get(decl.prop);
if (already) {
for (const report of [already, decl].filter((n) => !reported.has(n))) {
context.report({
node,
loc: report.loc,
messageId: 'unexpected',
data: { name: report.prop }
});
reported.add(report);
}
}
}
for (const decl of decls) {
beforeDeclarations.set(decl.prop, decl);
}
}
}
};
/** Iterate the style decl set from attrs */
function* iterateStyleDeclSetFromAttrs(attrs) {
for (const attr of attrs) {
if (attr.type === 'SvelteStyleDirective') {
yield {
decls: [{ prop: attr.key.name.name, loc: attr.key.name.loc }]
};
}
else if (attr.type === 'SvelteAttribute') {
if (attr.key.name !== 'style') {
continue;
}
const root = parseStyleAttributeValue(attr, context);
if (!root) {
continue;
}
yield* iterateStyleDeclSetFromStyleRoot(root);
}
}
}
/** Iterate the style decl set from style root */
function* iterateStyleDeclSetFromStyleRoot(root) {
for (const child of root.nodes) {
if (child.type === 'decl') {
yield {
decls: [
{
prop: child.prop.name,
get loc() {
return child.prop.loc;
}
}
]
};
}
else if (child.type === 'inline') {
const decls = [];
for (const root of child.getAllInlineStyles().values()) {
for (const set of iterateStyleDeclSetFromStyleRoot(root)) {
decls.push(...set.decls);
}
}
yield { decls };
}
}
}
}
});