no-spaces-around-equal-signs-in-attribute.ts

import { createRule } from '../utils';
import type { AST } from 'svelte-eslint-parser';

export default createRule('no-spaces-around-equal-signs-in-attribute', {
	meta: {
		docs: {
			description: 'disallow spaces around equal signs in attribute',
			category: 'Stylistic Issues',
			recommended: false,
			conflictWithPrettier: true
		},
		schema: [],
		fixable: 'whitespace',
		messages: {
			noSpaces: 'Unexpected spaces found around equal signs.'
		},
		type: 'layout'
	},
	create(ctx) {
		const source = ctx.getSourceCode();

		/**
		 * Returns source text between attribute key and value, and range of that source
		 */
		function getAttrEq(
			node:
				| AST.SvelteAttribute
				| AST.SvelteDirective
				| AST.SvelteStyleDirective
				| AST.SvelteSpecialDirective
		): [string, AST.Range] {
			const keyRange = node.key.range;
			const eqSource = /^[\s=]*/u.exec(source.text.slice(keyRange[1], node.range[1]))![0];
			const valueStart = keyRange[1] + eqSource.length;
			return [eqSource, [keyRange[1], valueStart]];
		}

		/**
		 * Returns true if string contains whitespace characters
		 */
		function containsWhitespace(string: string): boolean {
			return /\s/u.test(string);
		}

		return {
			'SvelteAttribute, SvelteDirective, SvelteStyleDirective, SvelteSpecialDirective'(
				node:
					| AST.SvelteAttribute
					| AST.SvelteDirective
					| AST.SvelteStyleDirective
					| AST.SvelteSpecialDirective
			) {
				const [eqSource, range] = getAttrEq(node);

				if (!containsWhitespace(eqSource)) return;

				const loc = {
					start: source.getLocFromIndex(range[0]),
					end: source.getLocFromIndex(range[1])
				};

				ctx.report({
					loc,
					messageId: 'noSpaces',
					*fix(fixer) {
						yield fixer.replaceTextRange(range, '=');
					}
				});
			}
		};
	}
});