source: imaps-frontend/node_modules/eslint/lib/rules/one-var.js@ d565449

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Last change on this file since d565449 was d565449, checked in by stefan toskovski <stefantoska84@…>, 4 weeks ago

Update repo after prototype presentation
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1/**
2 * @fileoverview A rule to control the use of single variable declarations.
3 * @author Ian Christian Myers
4 */
5
6"use strict";
7
8//------------------------------------------------------------------------------
9// Requirements
10//------------------------------------------------------------------------------
11
12const astUtils = require("./utils/ast-utils");
13
14//------------------------------------------------------------------------------
15// Helpers
16//------------------------------------------------------------------------------
17
18/**
19 * Determines whether the given node is in a statement list.
20 * @param {ASTNode} node node to check
21 * @returns {boolean} `true` if the given node is in a statement list
22 */
23function isInStatementList(node) {
24 return astUtils.STATEMENT_LIST_PARENTS.has(node.parent.type);
25}
26
27//------------------------------------------------------------------------------
28// Rule Definition
29//------------------------------------------------------------------------------
30
31/** @type {import('../shared/types').Rule} */
32module.exports = {
33 meta: {
34 type: "suggestion",
35
36 docs: {
37 description: "Enforce variables to be declared either together or separately in functions",
38 recommended: false,
39 url: "https://eslint.org/docs/latest/rules/one-var"
40 },
41
42 fixable: "code",
43
44 schema: [
45 {
46 oneOf: [
47 {
48 enum: ["always", "never", "consecutive"]
49 },
50 {
51 type: "object",
52 properties: {
53 separateRequires: {
54 type: "boolean"
55 },
56 var: {
57 enum: ["always", "never", "consecutive"]
58 },
59 let: {
60 enum: ["always", "never", "consecutive"]
61 },
62 const: {
63 enum: ["always", "never", "consecutive"]
64 }
65 },
66 additionalProperties: false
67 },
68 {
69 type: "object",
70 properties: {
71 initialized: {
72 enum: ["always", "never", "consecutive"]
73 },
74 uninitialized: {
75 enum: ["always", "never", "consecutive"]
76 }
77 },
78 additionalProperties: false
79 }
80 ]
81 }
82 ],
83
84 messages: {
85 combineUninitialized: "Combine this with the previous '{{type}}' statement with uninitialized variables.",
86 combineInitialized: "Combine this with the previous '{{type}}' statement with initialized variables.",
87 splitUninitialized: "Split uninitialized '{{type}}' declarations into multiple statements.",
88 splitInitialized: "Split initialized '{{type}}' declarations into multiple statements.",
89 splitRequires: "Split requires to be separated into a single block.",
90 combine: "Combine this with the previous '{{type}}' statement.",
91 split: "Split '{{type}}' declarations into multiple statements."
92 }
93 },
94
95 create(context) {
96 const MODE_ALWAYS = "always";
97 const MODE_NEVER = "never";
98 const MODE_CONSECUTIVE = "consecutive";
99 const mode = context.options[0] || MODE_ALWAYS;
100
101 const options = {};
102
103 if (typeof mode === "string") { // simple options configuration with just a string
104 options.var = { uninitialized: mode, initialized: mode };
105 options.let = { uninitialized: mode, initialized: mode };
106 options.const = { uninitialized: mode, initialized: mode };
107 } else if (typeof mode === "object") { // options configuration is an object
108 options.separateRequires = !!mode.separateRequires;
109 options.var = { uninitialized: mode.var, initialized: mode.var };
110 options.let = { uninitialized: mode.let, initialized: mode.let };
111 options.const = { uninitialized: mode.const, initialized: mode.const };
112 if (Object.prototype.hasOwnProperty.call(mode, "uninitialized")) {
113 options.var.uninitialized = mode.uninitialized;
114 options.let.uninitialized = mode.uninitialized;
115 options.const.uninitialized = mode.uninitialized;
116 }
117 if (Object.prototype.hasOwnProperty.call(mode, "initialized")) {
118 options.var.initialized = mode.initialized;
119 options.let.initialized = mode.initialized;
120 options.const.initialized = mode.initialized;
121 }
122 }
123
124 const sourceCode = context.sourceCode;
125
126 //--------------------------------------------------------------------------
127 // Helpers
128 //--------------------------------------------------------------------------
129
130 const functionStack = [];
131 const blockStack = [];
132
133 /**
134 * Increments the blockStack counter.
135 * @returns {void}
136 * @private
137 */
138 function startBlock() {
139 blockStack.push({
140 let: { initialized: false, uninitialized: false },
141 const: { initialized: false, uninitialized: false }
142 });
143 }
144
145 /**
146 * Increments the functionStack counter.
147 * @returns {void}
148 * @private
149 */
150 function startFunction() {
151 functionStack.push({ initialized: false, uninitialized: false });
152 startBlock();
153 }
154
155 /**
156 * Decrements the blockStack counter.
157 * @returns {void}
158 * @private
159 */
160 function endBlock() {
161 blockStack.pop();
162 }
163
164 /**
165 * Decrements the functionStack counter.
166 * @returns {void}
167 * @private
168 */
169 function endFunction() {
170 functionStack.pop();
171 endBlock();
172 }
173
174 /**
175 * Check if a variable declaration is a require.
176 * @param {ASTNode} decl variable declaration Node
177 * @returns {bool} if decl is a require, return true; else return false.
178 * @private
179 */
180 function isRequire(decl) {
181 return decl.init && decl.init.type === "CallExpression" && decl.init.callee.name === "require";
182 }
183
184 /**
185 * Records whether initialized/uninitialized/required variables are defined in current scope.
186 * @param {string} statementType node.kind, one of: "var", "let", or "const"
187 * @param {ASTNode[]} declarations List of declarations
188 * @param {Object} currentScope The scope being investigated
189 * @returns {void}
190 * @private
191 */
192 function recordTypes(statementType, declarations, currentScope) {
193 for (let i = 0; i < declarations.length; i++) {
194 if (declarations[i].init === null) {
195 if (options[statementType] && options[statementType].uninitialized === MODE_ALWAYS) {
196 currentScope.uninitialized = true;
197 }
198 } else {
199 if (options[statementType] && options[statementType].initialized === MODE_ALWAYS) {
200 if (options.separateRequires && isRequire(declarations[i])) {
201 currentScope.required = true;
202 } else {
203 currentScope.initialized = true;
204 }
205 }
206 }
207 }
208 }
209
210 /**
211 * Determines the current scope (function or block)
212 * @param {string} statementType node.kind, one of: "var", "let", or "const"
213 * @returns {Object} The scope associated with statementType
214 */
215 function getCurrentScope(statementType) {
216 let currentScope;
217
218 if (statementType === "var") {
219 currentScope = functionStack[functionStack.length - 1];
220 } else if (statementType === "let") {
221 currentScope = blockStack[blockStack.length - 1].let;
222 } else if (statementType === "const") {
223 currentScope = blockStack[blockStack.length - 1].const;
224 }
225 return currentScope;
226 }
227
228 /**
229 * Counts the number of initialized and uninitialized declarations in a list of declarations
230 * @param {ASTNode[]} declarations List of declarations
231 * @returns {Object} Counts of 'uninitialized' and 'initialized' declarations
232 * @private
233 */
234 function countDeclarations(declarations) {
235 const counts = { uninitialized: 0, initialized: 0 };
236
237 for (let i = 0; i < declarations.length; i++) {
238 if (declarations[i].init === null) {
239 counts.uninitialized++;
240 } else {
241 counts.initialized++;
242 }
243 }
244 return counts;
245 }
246
247 /**
248 * Determines if there is more than one var statement in the current scope.
249 * @param {string} statementType node.kind, one of: "var", "let", or "const"
250 * @param {ASTNode[]} declarations List of declarations
251 * @returns {boolean} Returns true if it is the first var declaration, false if not.
252 * @private
253 */
254 function hasOnlyOneStatement(statementType, declarations) {
255
256 const declarationCounts = countDeclarations(declarations);
257 const currentOptions = options[statementType] || {};
258 const currentScope = getCurrentScope(statementType);
259 const hasRequires = declarations.some(isRequire);
260
261 if (currentOptions.uninitialized === MODE_ALWAYS && currentOptions.initialized === MODE_ALWAYS) {
262 if (currentScope.uninitialized || currentScope.initialized) {
263 if (!hasRequires) {
264 return false;
265 }
266 }
267 }
268
269 if (declarationCounts.uninitialized > 0) {
270 if (currentOptions.uninitialized === MODE_ALWAYS && currentScope.uninitialized) {
271 return false;
272 }
273 }
274 if (declarationCounts.initialized > 0) {
275 if (currentOptions.initialized === MODE_ALWAYS && currentScope.initialized) {
276 if (!hasRequires) {
277 return false;
278 }
279 }
280 }
281 if (currentScope.required && hasRequires) {
282 return false;
283 }
284 recordTypes(statementType, declarations, currentScope);
285 return true;
286 }
287
288 /**
289 * Fixer to join VariableDeclaration's into a single declaration
290 * @param {VariableDeclarator[]} declarations The `VariableDeclaration` to join
291 * @returns {Function} The fixer function
292 */
293 function joinDeclarations(declarations) {
294 const declaration = declarations[0];
295 const body = Array.isArray(declaration.parent.parent.body) ? declaration.parent.parent.body : [];
296 const currentIndex = body.findIndex(node => node.range[0] === declaration.parent.range[0]);
297 const previousNode = body[currentIndex - 1];
298
299 return fixer => {
300 const type = sourceCode.getTokenBefore(declaration);
301 const prevSemi = sourceCode.getTokenBefore(type);
302 const res = [];
303
304 if (previousNode && previousNode.kind === sourceCode.getText(type)) {
305 if (prevSemi.value === ";") {
306 res.push(fixer.replaceText(prevSemi, ","));
307 } else {
308 res.push(fixer.insertTextAfter(prevSemi, ","));
309 }
310 res.push(fixer.replaceText(type, ""));
311 }
312
313 return res;
314 };
315 }
316
317 /**
318 * Fixer to split a VariableDeclaration into individual declarations
319 * @param {VariableDeclaration} declaration The `VariableDeclaration` to split
320 * @returns {Function|null} The fixer function
321 */
322 function splitDeclarations(declaration) {
323 const { parent } = declaration;
324
325 // don't autofix code such as: if (foo) var x, y;
326 if (!isInStatementList(parent.type === "ExportNamedDeclaration" ? parent : declaration)) {
327 return null;
328 }
329
330 return fixer => declaration.declarations.map(declarator => {
331 const tokenAfterDeclarator = sourceCode.getTokenAfter(declarator);
332
333 if (tokenAfterDeclarator === null) {
334 return null;
335 }
336
337 const afterComma = sourceCode.getTokenAfter(tokenAfterDeclarator, { includeComments: true });
338
339 if (tokenAfterDeclarator.value !== ",") {
340 return null;
341 }
342
343 const exportPlacement = declaration.parent.type === "ExportNamedDeclaration" ? "export " : "";
344
345 /*
346 * `var x,y`
347 * tokenAfterDeclarator ^^ afterComma
348 */
349 if (afterComma.range[0] === tokenAfterDeclarator.range[1]) {
350 return fixer.replaceText(tokenAfterDeclarator, `; ${exportPlacement}${declaration.kind} `);
351 }
352
353 /*
354 * `var x,
355 * tokenAfterDeclarator ^
356 * y`
357 * ^ afterComma
358 */
359 if (
360 afterComma.loc.start.line > tokenAfterDeclarator.loc.end.line ||
361 afterComma.type === "Line" ||
362 afterComma.type === "Block"
363 ) {
364 let lastComment = afterComma;
365
366 while (lastComment.type === "Line" || lastComment.type === "Block") {
367 lastComment = sourceCode.getTokenAfter(lastComment, { includeComments: true });
368 }
369
370 return fixer.replaceTextRange(
371 [tokenAfterDeclarator.range[0], lastComment.range[0]],
372 `;${sourceCode.text.slice(tokenAfterDeclarator.range[1], lastComment.range[0])}${exportPlacement}${declaration.kind} `
373 );
374 }
375
376 return fixer.replaceText(tokenAfterDeclarator, `; ${exportPlacement}${declaration.kind}`);
377 }).filter(x => x);
378 }
379
380 /**
381 * Checks a given VariableDeclaration node for errors.
382 * @param {ASTNode} node The VariableDeclaration node to check
383 * @returns {void}
384 * @private
385 */
386 function checkVariableDeclaration(node) {
387 const parent = node.parent;
388 const type = node.kind;
389
390 if (!options[type]) {
391 return;
392 }
393
394 const declarations = node.declarations;
395 const declarationCounts = countDeclarations(declarations);
396 const mixedRequires = declarations.some(isRequire) && !declarations.every(isRequire);
397
398 if (options[type].initialized === MODE_ALWAYS) {
399 if (options.separateRequires && mixedRequires) {
400 context.report({
401 node,
402 messageId: "splitRequires"
403 });
404 }
405 }
406
407 // consecutive
408 const nodeIndex = (parent.body && parent.body.length > 0 && parent.body.indexOf(node)) || 0;
409
410 if (nodeIndex > 0) {
411 const previousNode = parent.body[nodeIndex - 1];
412 const isPreviousNodeDeclaration = previousNode.type === "VariableDeclaration";
413 const declarationsWithPrevious = declarations.concat(previousNode.declarations || []);
414
415 if (
416 isPreviousNodeDeclaration &&
417 previousNode.kind === type &&
418 !(declarationsWithPrevious.some(isRequire) && !declarationsWithPrevious.every(isRequire))
419 ) {
420 const previousDeclCounts = countDeclarations(previousNode.declarations);
421
422 if (options[type].initialized === MODE_CONSECUTIVE && options[type].uninitialized === MODE_CONSECUTIVE) {
423 context.report({
424 node,
425 messageId: "combine",
426 data: {
427 type
428 },
429 fix: joinDeclarations(declarations)
430 });
431 } else if (options[type].initialized === MODE_CONSECUTIVE && declarationCounts.initialized > 0 && previousDeclCounts.initialized > 0) {
432 context.report({
433 node,
434 messageId: "combineInitialized",
435 data: {
436 type
437 },
438 fix: joinDeclarations(declarations)
439 });
440 } else if (options[type].uninitialized === MODE_CONSECUTIVE &&
441 declarationCounts.uninitialized > 0 &&
442 previousDeclCounts.uninitialized > 0) {
443 context.report({
444 node,
445 messageId: "combineUninitialized",
446 data: {
447 type
448 },
449 fix: joinDeclarations(declarations)
450 });
451 }
452 }
453 }
454
455 // always
456 if (!hasOnlyOneStatement(type, declarations)) {
457 if (options[type].initialized === MODE_ALWAYS && options[type].uninitialized === MODE_ALWAYS) {
458 context.report({
459 node,
460 messageId: "combine",
461 data: {
462 type
463 },
464 fix: joinDeclarations(declarations)
465 });
466 } else {
467 if (options[type].initialized === MODE_ALWAYS && declarationCounts.initialized > 0) {
468 context.report({
469 node,
470 messageId: "combineInitialized",
471 data: {
472 type
473 },
474 fix: joinDeclarations(declarations)
475 });
476 }
477 if (options[type].uninitialized === MODE_ALWAYS && declarationCounts.uninitialized > 0) {
478 if (node.parent.left === node && (node.parent.type === "ForInStatement" || node.parent.type === "ForOfStatement")) {
479 return;
480 }
481 context.report({
482 node,
483 messageId: "combineUninitialized",
484 data: {
485 type
486 },
487 fix: joinDeclarations(declarations)
488 });
489 }
490 }
491 }
492
493 // never
494 if (parent.type !== "ForStatement" || parent.init !== node) {
495 const totalDeclarations = declarationCounts.uninitialized + declarationCounts.initialized;
496
497 if (totalDeclarations > 1) {
498 if (options[type].initialized === MODE_NEVER && options[type].uninitialized === MODE_NEVER) {
499
500 // both initialized and uninitialized
501 context.report({
502 node,
503 messageId: "split",
504 data: {
505 type
506 },
507 fix: splitDeclarations(node)
508 });
509 } else if (options[type].initialized === MODE_NEVER && declarationCounts.initialized > 0) {
510
511 // initialized
512 context.report({
513 node,
514 messageId: "splitInitialized",
515 data: {
516 type
517 },
518 fix: splitDeclarations(node)
519 });
520 } else if (options[type].uninitialized === MODE_NEVER && declarationCounts.uninitialized > 0) {
521
522 // uninitialized
523 context.report({
524 node,
525 messageId: "splitUninitialized",
526 data: {
527 type
528 },
529 fix: splitDeclarations(node)
530 });
531 }
532 }
533 }
534 }
535
536 //--------------------------------------------------------------------------
537 // Public API
538 //--------------------------------------------------------------------------
539
540 return {
541 Program: startFunction,
542 FunctionDeclaration: startFunction,
543 FunctionExpression: startFunction,
544 ArrowFunctionExpression: startFunction,
545 StaticBlock: startFunction, // StaticBlock creates a new scope for `var` variables
546
547 BlockStatement: startBlock,
548 ForStatement: startBlock,
549 ForInStatement: startBlock,
550 ForOfStatement: startBlock,
551 SwitchStatement: startBlock,
552 VariableDeclaration: checkVariableDeclaration,
553 "ForStatement:exit": endBlock,
554 "ForOfStatement:exit": endBlock,
555 "ForInStatement:exit": endBlock,
556 "SwitchStatement:exit": endBlock,
557 "BlockStatement:exit": endBlock,
558
559 "Program:exit": endFunction,
560 "FunctionDeclaration:exit": endFunction,
561 "FunctionExpression:exit": endFunction,
562 "ArrowFunctionExpression:exit": endFunction,
563 "StaticBlock:exit": endFunction
564 };
565
566 }
567};
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