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 * Compares items in a fixes array by range.
120 * @param {Fix} a The first message.
121 * @param {Fix} b The second message.
122 * @returns {int} -1 if a comes before b, 1 if a comes after b, 0 if equal.
125 function compareFixesByRange(a, b) {
126 return a.range[0] - b.range[0] || a.range[1] - b.range[1];
130 * Merges the given fixes array into one.
131 * @param {Fix[]} fixes The fixes to merge.
132 * @param {SourceCode} sourceCode The source code object to get the text between fixes.
133 * @returns {{text: string, range: number[]}} The merged fixes
135 function mergeFixes(fixes, sourceCode) {
136 if (fixes.length === 0) {
139 if (fixes.length === 1) {
143 fixes.sort(compareFixesByRange);
145 const originalText = sourceCode.text;
146 const start = fixes[0].range[0];
147 const end = fixes[fixes.length - 1].range[1];
149 let lastPos = Number.MIN_SAFE_INTEGER;
151 for (const fix of fixes) {
152 assert(fix.range[0] >= lastPos, "Fix objects must not be overlapped in a report.");
154 if (fix.range[0] >= 0) {
155 text += originalText.slice(Math.max(0, start, lastPos), fix.range[0]);
158 lastPos = fix.range[1];
160 text += originalText.slice(Math.max(0, start, lastPos), end);
162 return { range: [start, end], text };
166 * Gets one fix object from the given descriptor.
167 * If the descriptor retrieves multiple fixes, this merges those to one.
168 * @param {MessageDescriptor} descriptor The report descriptor.
169 * @param {SourceCode} sourceCode The source code object to get text between fixes.
170 * @returns {({text: string, range: number[]}|null)} The fix for the descriptor
172 function normalizeFixes(descriptor, sourceCode) {
173 if (typeof descriptor.fix !== "function") {
177 // @type {null | Fix | Fix[] | IterableIterator<Fix>}
178 const fix = descriptor.fix(ruleFixer);
181 if (fix && Symbol.iterator in fix) {
182 return mergeFixes(Array.from(fix), sourceCode);
188 * Gets an array of suggestion objects from the given descriptor.
189 * @param {MessageDescriptor} descriptor The report descriptor.
190 * @param {SourceCode} sourceCode The source code object to get text between fixes.
191 * @param {Object} messages Object of meta messages for the rule.
192 * @returns {Array<SuggestionResult>} The suggestions for the descriptor
194 function mapSuggestions(descriptor, sourceCode, messages) {
195 if (!descriptor.suggest || !Array.isArray(descriptor.suggest)) {
199 return descriptor.suggest.map(suggestInfo => {
200 const computedDesc = suggestInfo.desc || messages[suggestInfo.messageId];
204 desc: interpolate(computedDesc, suggestInfo.data),
205 fix: normalizeFixes(suggestInfo, sourceCode)
211 * Creates information about the report from a descriptor
212 * @param {Object} options Information about the problem
213 * @param {string} options.ruleId Rule ID
214 * @param {(0|1|2)} options.severity Rule severity
215 * @param {(ASTNode|null)} options.node Node
216 * @param {string} options.message Error message
217 * @param {string} [options.messageId] The error message ID.
218 * @param {{start: SourceLocation, end: (SourceLocation|null)}} options.loc Start and end location
219 * @param {{text: string, range: (number[]|null)}} options.fix The fix object
220 * @param {Array<{text: string, range: (number[]|null)}>} options.suggestions The array of suggestions objects
221 * @returns {function(...args): ReportInfo} Function that returns information about the report
223 function createProblem(options) {
225 ruleId: options.ruleId,
226 severity: options.severity,
227 message: options.message,
228 line: options.loc.start.line,
229 column: options.loc.start.column + 1,
230 nodeType: options.node && options.node.type || null
234 * If this isn’t in the conditional, some of the tests fail
235 * because `messageId` is present in the problem object
237 if (options.messageId) {
238 problem.messageId = options.messageId;
241 if (options.loc.end) {
242 problem.endLine = options.loc.end.line;
243 problem.endColumn = options.loc.end.column + 1;
247 problem.fix = options.fix;
250 if (options.suggestions && options.suggestions.length > 0) {
251 problem.suggestions = options.suggestions;
258 * Validates that suggestions are properly defined. Throws if an error is detected.
259 * @param {Array<{ desc?: string, messageId?: string }>} suggest The incoming suggest data.
260 * @param {Object} messages Object of meta messages for the rule.
263 function validateSuggestions(suggest, messages) {
264 if (suggest && Array.isArray(suggest)) {
265 suggest.forEach(suggestion => {
266 if (suggestion.messageId) {
267 const { messageId } = suggestion;
270 throw new TypeError(`context.report() called with a suggest option with a messageId '${messageId}', but no messages were present in the rule metadata.`);
273 if (!messages[messageId]) {
274 throw new TypeError(`context.report() called with a suggest option with a messageId '${messageId}' which is not present in the 'messages' config: ${JSON.stringify(messages, null, 2)}`);
277 if (suggestion.desc) {
278 throw new TypeError("context.report() called with a suggest option that defines both a 'messageId' and an 'desc'. Please only pass one.");
280 } else if (!suggestion.desc) {
281 throw new TypeError("context.report() called with a suggest option that doesn't have either a `desc` or `messageId`");
284 if (typeof suggestion.fix !== "function") {
285 throw new TypeError(`context.report() called with a suggest option without a fix function. See: ${suggestion}`);
292 * Returns a function that converts the arguments of a `context.report` call from a rule into a reported
293 * problem for the Node.js API.
294 * @param {{ruleId: string, severity: number, sourceCode: SourceCode, messageIds: Object, disableFixes: boolean}} metadata Metadata for the reported problem
295 * @param {SourceCode} sourceCode The `SourceCode` instance for the text being linted
296 * @returns {function(...args): ReportInfo} Function that returns information about the report
299 module.exports = function createReportTranslator(metadata) {
302 * `createReportTranslator` gets called once per enabled rule per file. It needs to be very performant.
303 * The report translator itself (i.e. the function that `createReportTranslator` returns) gets
304 * called every time a rule reports a problem, which happens much less frequently (usually, the vast
305 * majority of rules don't report any problems for a given file).
307 return (...args) => {
308 const descriptor = normalizeMultiArgReportCall(...args);
309 const messages = metadata.messageIds;
311 assertValidNodeInfo(descriptor);
315 if (descriptor.messageId) {
317 throw new TypeError("context.report() called with a messageId, but no messages were present in the rule metadata.");
319 const id = descriptor.messageId;
321 if (descriptor.message) {
322 throw new TypeError("context.report() called with a message and a messageId. Please only pass one.");
324 if (!messages || !Object.prototype.hasOwnProperty.call(messages, id)) {
325 throw new TypeError(`context.report() called with a messageId of '${id}' which is not present in the 'messages' config: ${JSON.stringify(messages, null, 2)}`);
327 computedMessage = messages[id];
328 } else if (descriptor.message) {
329 computedMessage = descriptor.message;
331 throw new TypeError("Missing `message` property in report() call; add a message that describes the linting problem.");
334 validateSuggestions(descriptor.suggest, messages);
336 return createProblem({
337 ruleId: metadata.ruleId,
338 severity: metadata.severity,
339 node: descriptor.node,
340 message: interpolate(computedMessage, descriptor.data),
341 messageId: descriptor.messageId,
342 loc: normalizeReportLoc(descriptor),
343 fix: metadata.disableFixes ? null : normalizeFixes(descriptor, metadata.sourceCode),
344 suggestions: metadata.disableFixes ? [] : mapSuggestions(descriptor, metadata.sourceCode, messages)