2 * @fileoverview A helper that translates context.report() calls from the rule API into generic problem objects
8 //------------------------------------------------------------------------------
10 //------------------------------------------------------------------------------
12 const assert = require("assert");
13 const ruleFixer = require("./rule-fixer");
14 const interpolate = require("./interpolate");
16 //------------------------------------------------------------------------------
18 //------------------------------------------------------------------------------
21 * An error message description
22 * @typedef {Object} MessageDescriptor
23 * @property {ASTNode} [node] The reported node
24 * @property {Location} loc The location of the problem.
25 * @property {string} message The problem message.
26 * @property {Object} [data] Optional data to use to fill in placeholders in the
28 * @property {Function} [fix] The function to call that creates a fix command.
29 * @property {Array<{desc?: string, messageId?: string, fix: Function}>} suggest Suggestion descriptions and functions to create a the associated fixes.
33 * Information about the report
34 * @typedef {Object} ReportInfo
35 * @property {string} ruleId
36 * @property {(0|1|2)} severity
37 * @property {(string|undefined)} message
38 * @property {(string|undefined)} [messageId]
39 * @property {number} line
40 * @property {number} column
41 * @property {(number|undefined)} [endLine]
42 * @property {(number|undefined)} [endColumn]
43 * @property {(string|null)} nodeType
44 * @property {string} source
45 * @property {({text: string, range: (number[]|null)}|null)} [fix]
46 * @property {Array<{text: string, range: (number[]|null)}|null>} [suggestions]
49 //------------------------------------------------------------------------------
51 //------------------------------------------------------------------------------
55 * Translates a multi-argument context.report() call into a single object argument call
56 * @param {...*} args A list of arguments passed to `context.report`
57 * @returns {MessageDescriptor} A normalized object containing report information
59 function normalizeMultiArgReportCall(...args) {
61 // If there is one argument, it is considered to be a new-style call already.
62 if (args.length === 1) {
64 // Shallow clone the object to avoid surprises if reusing the descriptor
65 return Object.assign({}, args[0]);
68 // If the second argument is a string, the arguments are interpreted as [node, message, data, fix].
69 if (typeof args[1] === "string") {
78 // Otherwise, the arguments are interpreted as [node, loc, message, data, fix].
89 * Asserts that either a loc or a node was provided, and the node is valid if it was provided.
90 * @param {MessageDescriptor} descriptor A descriptor to validate
92 * @throws AssertionError if neither a node nor a loc was provided, or if the node is not an object
94 function assertValidNodeInfo(descriptor) {
95 if (descriptor.node) {
96 assert(typeof descriptor.node === "object", "Node must be an object");
98 assert(descriptor.loc, "Node must be provided when reporting error if location is not provided");
103 * Normalizes a MessageDescriptor to always have a `loc` with `start` and `end` properties
104 * @param {MessageDescriptor} descriptor A descriptor for the report from a rule.
105 * @returns {{start: Location, end: (Location|null)}} An updated location that infers the `start` and `end` properties
106 * from the `node` of the original descriptor, or infers the `start` from the `loc` of the original descriptor.
108 function normalizeReportLoc(descriptor) {
109 if (descriptor.loc) {
110 if (descriptor.loc.start) {
111 return descriptor.loc;
113 return { start: descriptor.loc, end: null };
115 return descriptor.node.loc;
119 * Check that a fix has a valid range.
120 * @param {Fix|null} fix The fix to validate.
123 function assertValidFix(fix) {
125 assert(fix.range && typeof fix.range[0] === "number" && typeof fix.range[1] === "number", `Fix has invalid range: ${JSON.stringify(fix, null, 2)}`);
130 * Compares items in a fixes array by range.
131 * @param {Fix} a The first message.
132 * @param {Fix} b The second message.
133 * @returns {int} -1 if a comes before b, 1 if a comes after b, 0 if equal.
136 function compareFixesByRange(a, b) {
137 return a.range[0] - b.range[0] || a.range[1] - b.range[1];
141 * Merges the given fixes array into one.
142 * @param {Fix[]} fixes The fixes to merge.
143 * @param {SourceCode} sourceCode The source code object to get the text between fixes.
144 * @returns {{text: string, range: number[]}} The merged fixes
146 function mergeFixes(fixes, sourceCode) {
147 for (const fix of fixes) {
151 if (fixes.length === 0) {
154 if (fixes.length === 1) {
158 fixes.sort(compareFixesByRange);
160 const originalText = sourceCode.text;
161 const start = fixes[0].range[0];
162 const end = fixes[fixes.length - 1].range[1];
164 let lastPos = Number.MIN_SAFE_INTEGER;
166 for (const fix of fixes) {
167 assert(fix.range[0] >= lastPos, "Fix objects must not be overlapped in a report.");
169 if (fix.range[0] >= 0) {
170 text += originalText.slice(Math.max(0, start, lastPos), fix.range[0]);
173 lastPos = fix.range[1];
175 text += originalText.slice(Math.max(0, start, lastPos), end);
177 return { range: [start, end], text };
181 * Gets one fix object from the given descriptor.
182 * If the descriptor retrieves multiple fixes, this merges those to one.
183 * @param {MessageDescriptor} descriptor The report descriptor.
184 * @param {SourceCode} sourceCode The source code object to get text between fixes.
185 * @returns {({text: string, range: number[]}|null)} The fix for the descriptor
187 function normalizeFixes(descriptor, sourceCode) {
188 if (typeof descriptor.fix !== "function") {
192 // @type {null | Fix | Fix[] | IterableIterator<Fix>}
193 const fix = descriptor.fix(ruleFixer);
196 if (fix && Symbol.iterator in fix) {
197 return mergeFixes(Array.from(fix), sourceCode);
205 * Gets an array of suggestion objects from the given descriptor.
206 * @param {MessageDescriptor} descriptor The report descriptor.
207 * @param {SourceCode} sourceCode The source code object to get text between fixes.
208 * @param {Object} messages Object of meta messages for the rule.
209 * @returns {Array<SuggestionResult>} The suggestions for the descriptor
211 function mapSuggestions(descriptor, sourceCode, messages) {
212 if (!descriptor.suggest || !Array.isArray(descriptor.suggest)) {
216 return descriptor.suggest
217 .map(suggestInfo => {
218 const computedDesc = suggestInfo.desc || messages[suggestInfo.messageId];
222 desc: interpolate(computedDesc, suggestInfo.data),
223 fix: normalizeFixes(suggestInfo, sourceCode)
227 // Remove suggestions that didn't provide a fix
228 .filter(({ fix }) => fix);
232 * Creates information about the report from a descriptor
233 * @param {Object} options Information about the problem
234 * @param {string} options.ruleId Rule ID
235 * @param {(0|1|2)} options.severity Rule severity
236 * @param {(ASTNode|null)} options.node Node
237 * @param {string} options.message Error message
238 * @param {string} [options.messageId] The error message ID.
239 * @param {{start: SourceLocation, end: (SourceLocation|null)}} options.loc Start and end location
240 * @param {{text: string, range: (number[]|null)}} options.fix The fix object
241 * @param {Array<{text: string, range: (number[]|null)}>} options.suggestions The array of suggestions objects
242 * @returns {function(...args): ReportInfo} Function that returns information about the report
244 function createProblem(options) {
246 ruleId: options.ruleId,
247 severity: options.severity,
248 message: options.message,
249 line: options.loc.start.line,
250 column: options.loc.start.column + 1,
251 nodeType: options.node && options.node.type || null
255 * If this isn’t in the conditional, some of the tests fail
256 * because `messageId` is present in the problem object
258 if (options.messageId) {
259 problem.messageId = options.messageId;
262 if (options.loc.end) {
263 problem.endLine = options.loc.end.line;
264 problem.endColumn = options.loc.end.column + 1;
268 problem.fix = options.fix;
271 if (options.suggestions && options.suggestions.length > 0) {
272 problem.suggestions = options.suggestions;
279 * Validates that suggestions are properly defined. Throws if an error is detected.
280 * @param {Array<{ desc?: string, messageId?: string }>} suggest The incoming suggest data.
281 * @param {Object} messages Object of meta messages for the rule.
284 function validateSuggestions(suggest, messages) {
285 if (suggest && Array.isArray(suggest)) {
286 suggest.forEach(suggestion => {
287 if (suggestion.messageId) {
288 const { messageId } = suggestion;
291 throw new TypeError(`context.report() called with a suggest option with a messageId '${messageId}', but no messages were present in the rule metadata.`);
294 if (!messages[messageId]) {
295 throw new TypeError(`context.report() called with a suggest option with a messageId '${messageId}' which is not present in the 'messages' config: ${JSON.stringify(messages, null, 2)}`);
298 if (suggestion.desc) {
299 throw new TypeError("context.report() called with a suggest option that defines both a 'messageId' and an 'desc'. Please only pass one.");
301 } else if (!suggestion.desc) {
302 throw new TypeError("context.report() called with a suggest option that doesn't have either a `desc` or `messageId`");
305 if (typeof suggestion.fix !== "function") {
306 throw new TypeError(`context.report() called with a suggest option without a fix function. See: ${suggestion}`);
313 * Returns a function that converts the arguments of a `context.report` call from a rule into a reported
314 * problem for the Node.js API.
315 * @param {{ruleId: string, severity: number, sourceCode: SourceCode, messageIds: Object, disableFixes: boolean}} metadata Metadata for the reported problem
316 * @param {SourceCode} sourceCode The `SourceCode` instance for the text being linted
317 * @returns {function(...args): ReportInfo} Function that returns information about the report
320 module.exports = function createReportTranslator(metadata) {
323 * `createReportTranslator` gets called once per enabled rule per file. It needs to be very performant.
324 * The report translator itself (i.e. the function that `createReportTranslator` returns) gets
325 * called every time a rule reports a problem, which happens much less frequently (usually, the vast
326 * majority of rules don't report any problems for a given file).
328 return (...args) => {
329 const descriptor = normalizeMultiArgReportCall(...args);
330 const messages = metadata.messageIds;
332 assertValidNodeInfo(descriptor);
336 if (descriptor.messageId) {
338 throw new TypeError("context.report() called with a messageId, but no messages were present in the rule metadata.");
340 const id = descriptor.messageId;
342 if (descriptor.message) {
343 throw new TypeError("context.report() called with a message and a messageId. Please only pass one.");
345 if (!messages || !Object.prototype.hasOwnProperty.call(messages, id)) {
346 throw new TypeError(`context.report() called with a messageId of '${id}' which is not present in the 'messages' config: ${JSON.stringify(messages, null, 2)}`);
348 computedMessage = messages[id];
349 } else if (descriptor.message) {
350 computedMessage = descriptor.message;
352 throw new TypeError("Missing `message` property in report() call; add a message that describes the linting problem.");
355 validateSuggestions(descriptor.suggest, messages);
357 return createProblem({
358 ruleId: metadata.ruleId,
359 severity: metadata.severity,
360 node: descriptor.node,
361 message: interpolate(computedMessage, descriptor.data),
362 messageId: descriptor.messageId,
363 loc: normalizeReportLoc(descriptor),
364 fix: metadata.disableFixes ? null : normalizeFixes(descriptor, metadata.sourceCode),
365 suggestions: metadata.disableFixes ? [] : mapSuggestions(descriptor, metadata.sourceCode, messages)