wehub-resource-sync
76 lines
2.4 KiB
JavaScript
76 lines
2.4 KiB
JavaScript
/**
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* ESLint rule to enforce that import statements are at the top of MDX files.
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*
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* The MDX parser strips markdown content from the AST, so standard rules like
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* `import/first` cannot detect imports placed after markdown content. This rule
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* checks the raw source text to find non-ESM content between imports.
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*
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* @type {import('eslint').Rule.RuleModule}
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*/
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module.exports = {
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meta: {
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type: 'problem',
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docs: {
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description: 'Enforce that import statements are at the top of MDX files',
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category: 'Best Practices',
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},
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fixable: null,
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schema: [],
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messages: {
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importNotAtTop: 'Import "{{source}}" should be at the top of the file. Move all imports before any content.',
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},
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},
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create(context) {
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return {
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Program(node) {
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const sourceCode = context.sourceCode || context.getSourceCode();
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const text = sourceCode.getText();
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const lines = text.split('\n');
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// Collect line numbers occupied by ESM nodes (imports/exports)
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const esmLines = new Set();
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for (const child of node.body) {
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for (let line = child.loc.start.line; line <= child.loc.end.line; line++) {
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esmLines.add(line);
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}
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}
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// Skip frontmatter (---...---) lines
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const frontmatterLines = new Set();
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if (lines[0]?.trim() === '---') {
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frontmatterLines.add(1);
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for (let i = 1; i < lines.length; i++) {
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frontmatterLines.add(i + 1);
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if (lines[i].trim() === '---') break;
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}
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}
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// Find the first line with non-whitespace content that is not ESM or frontmatter
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let firstContentLine = null;
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for (let i = 0; i < lines.length; i++) {
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const lineNum = i + 1; // 1-indexed
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if (esmLines.has(lineNum)) continue;
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if (frontmatterLines.has(lineNum)) continue;
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if (lines[i].trim() === '') continue;
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firstContentLine = lineNum;
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break;
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}
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if (firstContentLine === null) return;
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// Report any imports that appear after the first content line
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for (const child of node.body) {
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if (child.type === 'ImportDeclaration' && child.loc.start.line > firstContentLine) {
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context.report({
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node: child,
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messageId: 'importNotAtTop',
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data: { source: child.source.value },
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});
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}
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}
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},
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};
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},
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};
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