eslint-plugin-svelte/lib/rules/valid-prop-names-in-kit-pages.js

ESLint plugin for Svelte using AST

import { createRule } from '../utils/index.js';
import { getSvelteVersion } from '../utils/svelte-context.js';
const EXPECTED_PROP_NAMES = ['data', 'errors', 'form', 'params', 'snapshot'];
const EXPECTED_PROP_NAMES_SVELTE5 = [...EXPECTED_PROP_NAMES, 'children'];
function checkProp(node, context, expectedPropNames) {
    if (node.id.type !== 'ObjectPattern')
        return;
    for (const p of node.id.properties) {
        if (p.type === 'Property' &&
            p.key.type === 'Identifier' &&
            !expectedPropNames.includes(p.key.name)) {
            context.report({
                node: p.key,
                loc: p.key.loc,
                messageId: 'unexpected'
            });
        }
    }
}
function isModuleScript(node) {
    // <script context="module">
    if (node.key.name === 'context' &&
        node.value.some((v) => v.type === 'SvelteLiteral' && v.value === 'module')) {
        return true;
    }
    // <script module>
    if (node.key.name === 'module' && node.value.length === 0) {
        return true;
    }
    return false;
}
export default createRule('valid-prop-names-in-kit-pages', {
    meta: {
        docs: {
            description: 'disallow props other than data or errors in SvelteKit page components.',
            category: 'SvelteKit',
            recommended: true
        },
        schema: [],
        messages: {
            unexpected: 'disallow props other than data or errors in SvelteKit page components.'
        },
        type: 'problem',
        conditions: [
            {
                svelteKitFileTypes: ['+page.svelte', '+error.svelte', '+layout.svelte']
            }
        ]
    },
    create(context) {
        let isScript = false;
        const isSvelte5 = getSvelteVersion() === '5';
        const expectedPropNames = isSvelte5 ? EXPECTED_PROP_NAMES_SVELTE5 : EXPECTED_PROP_NAMES;
        return {
            // <script>
            'Program > SvelteScriptElement > SvelteStartTag': (node) => {
                // except for <script context="module">
                isScript = !node.attributes.some((a) => a.type === 'SvelteAttribute' && isModuleScript(a));
            },
            // </script>
            'Program > SvelteScriptElement:exit': () => {
                isScript = false;
            },
            // Svelte3,4
            'ExportNamedDeclaration > VariableDeclaration > VariableDeclarator': (node) => {
                if (!isScript)
                    return;
                // export let foo
                if (node.id.type === 'Identifier') {
                    if (!expectedPropNames.includes(node.id.name)) {
                        context.report({
                            node,
                            loc: node.loc,
                            messageId: 'unexpected'
                        });
                    }
                    return;
                }
                // export let { xxx, yyy } = zzz
                checkProp(node, context, expectedPropNames);
            },
            // Svelte5
            // let { foo, bar } = $props();
            'VariableDeclaration > VariableDeclarator': (node) => {
                if (!isScript)
                    return;
                if (node.init?.type !== 'CallExpression' ||
                    node.init.callee?.type !== 'Identifier' ||
                    node.init.callee?.name !== '$props') {
                    return;
                }
                checkProp(node, context, expectedPropNames);
            }
        };
    }
});