/**
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* @fileoverview Runs `prettier` as an ESLint rule.
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* @author Andres Suarez
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*/
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'use strict';
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// ------------------------------------------------------------------------------
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// Requirements
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// ------------------------------------------------------------------------------
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const fs = require('fs');
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const path = require('path');
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const {
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showInvisibles,
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generateDifferences
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} = require('prettier-linter-helpers');
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// ------------------------------------------------------------------------------
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// Constants
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// ------------------------------------------------------------------------------
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const { INSERT, DELETE, REPLACE } = generateDifferences;
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// ------------------------------------------------------------------------------
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// Privates
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// ------------------------------------------------------------------------------
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// Lazily-loaded Prettier.
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/**
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* @type {import('prettier')}
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*/
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let prettier;
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// ------------------------------------------------------------------------------
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// Rule Definition
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// ------------------------------------------------------------------------------
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/**
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* Reports a difference.
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* @param {import('eslint').Rule.RuleContext} context - The ESLint rule context.
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* @param {import('prettier-linter-helpers').Difference} difference - The difference object.
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* @returns {void}
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*/
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function reportDifference(context, difference) {
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const { operation, offset, deleteText = '', insertText = '' } = difference;
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const range = [offset, offset + deleteText.length];
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const [start, end] = range.map(index =>
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context.getSourceCode().getLocFromIndex(index)
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);
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context.report({
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messageId: operation,
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data: {
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deleteText: showInvisibles(deleteText),
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insertText: showInvisibles(insertText)
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},
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loc: { start, end },
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fix: fixer => fixer.replaceTextRange(range, insertText)
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});
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}
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/**
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* Given a filepath, get the nearest path that is a regular file.
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* The filepath provided by eslint may be a virtual filepath rather than a file
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* on disk. This attempts to transform a virtual path into an on-disk path
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* @param {string} filepath
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* @returns {string}
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*/
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function getOnDiskFilepath(filepath) {
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try {
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if (fs.statSync(filepath).isFile()) {
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return filepath;
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}
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} catch (err) {
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// https://github.com/eslint/eslint/issues/11989
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if (err.code === 'ENOTDIR') {
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return getOnDiskFilepath(path.dirname(filepath));
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}
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}
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return filepath;
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}
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// ------------------------------------------------------------------------------
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// Module Definition
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// ------------------------------------------------------------------------------
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module.exports = {
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configs: {
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recommended: {
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extends: ['prettier'],
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plugins: ['prettier'],
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rules: {
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'prettier/prettier': 'error',
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'arrow-body-style': 'off',
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'prefer-arrow-callback': 'off'
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}
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}
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},
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rules: {
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prettier: {
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meta: {
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docs: {
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url: 'https://github.com/prettier/eslint-plugin-prettier#options'
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},
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type: 'layout',
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fixable: 'code',
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schema: [
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// Prettier options:
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{
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type: 'object',
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properties: {},
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additionalProperties: true
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},
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{
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type: 'object',
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properties: {
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usePrettierrc: { type: 'boolean' },
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fileInfoOptions: {
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type: 'object',
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properties: {},
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additionalProperties: true
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}
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},
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additionalProperties: true
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}
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],
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messages: {
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[INSERT]: 'Insert `{{ insertText }}`',
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[DELETE]: 'Delete `{{ deleteText }}`',
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[REPLACE]: 'Replace `{{ deleteText }}` with `{{ insertText }}`'
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}
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},
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create(context) {
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const usePrettierrc =
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!context.options[1] || context.options[1].usePrettierrc !== false;
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const eslintFileInfoOptions =
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(context.options[1] && context.options[1].fileInfoOptions) || {};
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const sourceCode = context.getSourceCode();
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const filepath = context.getFilename();
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// Processors that extract content from a file, such as the markdown
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// plugin extracting fenced code blocks may choose to specify virtual
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// file paths. If this is the case then we need to resolve prettier
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// config and file info using the on-disk path instead of the virtual
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// path.
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// See https://github.com/eslint/eslint/issues/11989 for ideas around
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// being able to get this value directly from eslint in the future.
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const onDiskFilepath = getOnDiskFilepath(filepath);
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const source = sourceCode.text;
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return {
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Program() {
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if (!prettier) {
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// Prettier is expensive to load, so only load it if needed.
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prettier = require('prettier');
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}
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const eslintPrettierOptions = context.options[0] || {};
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const prettierRcOptions = usePrettierrc
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? prettier.resolveConfig.sync(onDiskFilepath, {
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editorconfig: true
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})
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: null;
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const { ignored, inferredParser } = prettier.getFileInfo.sync(
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onDiskFilepath,
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Object.assign(
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{},
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{ resolveConfig: true, ignorePath: '.prettierignore' },
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eslintFileInfoOptions
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)
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);
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// Skip if file is ignored using a .prettierignore file
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if (ignored) {
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return;
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}
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const initialOptions = {};
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// ESLint supports processors that let you extract and lint JS
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// fragments within a non-JS language. In the cases where prettier
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// supports the same language as a processor, we want to process
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// the provided source code as javascript (as ESLint provides the
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// rules with fragments of JS) instead of guessing the parser
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// based off the filename. Otherwise, for instance, on a .md file we
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// end up trying to run prettier over a fragment of JS using the
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// markdown parser, which throws an error.
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// Processors may set virtual filenames for these extracted blocks.
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// If they do so then we want to trust the file extension they
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// provide, and no override is needed.
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// If the processor does not set any virtual filename (signified by
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// `filepath` and `onDiskFilepath` being equal) AND we can't
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// infer the parser from the filename, either because no filename
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// was provided or because there is no parser found for the
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// filename, use javascript.
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// This is added to the options first, so that
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// prettierRcOptions and eslintPrettierOptions can still override
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// the parser.
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//
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// `parserBlocklist` should contain the list of prettier parser
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// names for file types where:
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// * Prettier supports parsing the file type
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// * There is an ESLint processor that extracts JavaScript snippets
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// from the file type.
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const parserBlocklist = [null, 'markdown', 'html'];
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let inferParserToBabel =
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parserBlocklist.indexOf(inferredParser) !== -1;
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if (
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// it could be processed by `@graphql-eslint/eslint-plugin` or `eslint-plugin-graphql`
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inferredParser === 'graphql' &&
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// for `eslint-plugin-graphql`, see https://github.com/apollographql/eslint-plugin-graphql/blob/master/src/index.js#L416
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source.startsWith('ESLintPluginGraphQLFile`')
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) {
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inferParserToBabel = true;
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}
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if (filepath === onDiskFilepath && inferParserToBabel) {
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// Prettier v1.16.0 renamed the `babylon` parser to `babel`
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// Use the modern name if available
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const supportBabelParser = prettier
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.getSupportInfo()
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.languages.some(language => language.parsers.includes('babel'));
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initialOptions.parser = supportBabelParser ? 'babel' : 'babylon';
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}
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const prettierOptions = Object.assign(
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{},
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initialOptions,
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prettierRcOptions,
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eslintPrettierOptions,
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{ filepath }
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);
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// prettier.format() may throw a SyntaxError if it cannot parse the
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// source code it is given. Usually for JS files this isn't a
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// problem as ESLint will report invalid syntax before trying to
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// pass it to the prettier plugin. However this might be a problem
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// for non-JS languages that are handled by a plugin. Notably Vue
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// files throw an error if they contain unclosed elements, such as
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// `<template><div></template>. In this case report an error at the
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// point at which parsing failed.
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let prettierSource;
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try {
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prettierSource = prettier.format(source, prettierOptions);
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} catch (err) {
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if (!(err instanceof SyntaxError)) {
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throw err;
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}
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let message = 'Parsing error: ' + err.message;
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// Prettier's message contains a codeframe style preview of the
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// invalid code and the line/column at which the error occurred.
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// ESLint shows those pieces of information elsewhere already so
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// remove them from the message
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if (err.codeFrame) {
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message = message.replace(`\n${err.codeFrame}`, '');
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}
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if (err.loc) {
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message = message.replace(/ \(\d+:\d+\)$/, '');
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}
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context.report({ message, loc: err.loc });
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return;
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}
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if (source !== prettierSource) {
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const differences = generateDifferences(source, prettierSource);
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for (const difference of differences) {
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reportDifference(context, difference);
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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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};
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