2 * @fileoverview Rule to specify spacing of object literal keys and values
3 * @author Brandon Mills
7 //------------------------------------------------------------------------------
9 //------------------------------------------------------------------------------
11 const astUtils = require("./utils/ast-utils");
13 //------------------------------------------------------------------------------
15 //------------------------------------------------------------------------------
18 * Checks whether a string contains a line terminator as defined in
19 * http://www.ecma-international.org/ecma-262/5.1/#sec-7.3
20 * @param {string} str String to test.
21 * @returns {boolean} True if str contains a line terminator.
23 function containsLineTerminator(str) {
24 return astUtils.LINEBREAK_MATCHER.test(str);
28 * Gets the last element of an array.
29 * @param {Array} arr An array.
30 * @returns {any} Last element of arr.
33 return arr[arr.length - 1];
37 * Checks whether a node is contained on a single line.
38 * @param {ASTNode} node AST Node being evaluated.
39 * @returns {boolean} True if the node is a single line.
41 function isSingleLine(node) {
42 return (node.loc.end.line === node.loc.start.line);
46 * Checks whether the properties on a single line.
47 * @param {ASTNode[]} properties List of Property AST nodes.
48 * @returns {boolean} True if all properies is on a single line.
50 function isSingleLineProperties(properties) {
51 const [firstProp] = properties,
52 lastProp = last(properties);
54 return firstProp.loc.start.line === lastProp.loc.end.line;
58 * Initializes a single option property from the configuration with defaults for undefined values
59 * @param {Object} toOptions Object to be initialized
60 * @param {Object} fromOptions Object to be initialized from
61 * @returns {Object} The object with correctly initialized options and values
63 function initOptionProperty(toOptions, fromOptions) {
64 toOptions.mode = fromOptions.mode || "strict";
66 // Set value of beforeColon
67 if (typeof fromOptions.beforeColon !== "undefined") {
68 toOptions.beforeColon = +fromOptions.beforeColon;
70 toOptions.beforeColon = 0;
73 // Set value of afterColon
74 if (typeof fromOptions.afterColon !== "undefined") {
75 toOptions.afterColon = +fromOptions.afterColon;
77 toOptions.afterColon = 1;
80 // Set align if exists
81 if (typeof fromOptions.align !== "undefined") {
82 if (typeof fromOptions.align === "object") {
83 toOptions.align = fromOptions.align;
86 on: fromOptions.align,
88 beforeColon: toOptions.beforeColon,
89 afterColon: toOptions.afterColon
98 * Initializes all the option values (singleLine, multiLine and align) from the configuration with defaults for undefined values
99 * @param {Object} toOptions Object to be initialized
100 * @param {Object} fromOptions Object to be initialized from
101 * @returns {Object} The object with correctly initialized options and values
103 function initOptions(toOptions, fromOptions) {
104 if (typeof fromOptions.align === "object") {
106 // Initialize the alignment configuration
107 toOptions.align = initOptionProperty({}, fromOptions.align);
108 toOptions.align.on = fromOptions.align.on || "colon";
109 toOptions.align.mode = fromOptions.align.mode || "strict";
111 toOptions.multiLine = initOptionProperty({}, (fromOptions.multiLine || fromOptions));
112 toOptions.singleLine = initOptionProperty({}, (fromOptions.singleLine || fromOptions));
114 } else { // string or undefined
115 toOptions.multiLine = initOptionProperty({}, (fromOptions.multiLine || fromOptions));
116 toOptions.singleLine = initOptionProperty({}, (fromOptions.singleLine || fromOptions));
118 // If alignment options are defined in multiLine, pull them out into the general align configuration
119 if (toOptions.multiLine.align) {
121 on: toOptions.multiLine.align.on,
122 mode: toOptions.multiLine.align.mode || toOptions.multiLine.mode,
123 beforeColon: toOptions.multiLine.align.beforeColon,
124 afterColon: toOptions.multiLine.align.afterColon
132 //------------------------------------------------------------------------------
134 //------------------------------------------------------------------------------
141 description: "enforce consistent spacing between keys and values in object literal properties",
142 category: "Stylistic Issues",
144 url: "https://eslint.org/docs/rules/key-spacing"
147 fixable: "whitespace",
157 enum: ["colon", "value"]
163 enum: ["strict", "minimum"]
166 enum: ["colon", "value"]
175 additionalProperties: false
180 enum: ["strict", "minimum"]
189 additionalProperties: false
198 enum: ["strict", "minimum"]
207 additionalProperties: false
215 enum: ["colon", "value"]
221 enum: ["strict", "minimum"]
224 enum: ["colon", "value"]
233 additionalProperties: false
238 enum: ["strict", "minimum"]
247 additionalProperties: false
250 additionalProperties: false
259 enum: ["strict", "minimum"]
268 additionalProperties: false
274 enum: ["strict", "minimum"]
283 additionalProperties: false
289 enum: ["strict", "minimum"]
292 enum: ["colon", "value"]
301 additionalProperties: false
304 additionalProperties: false
309 extraKey: "Extra space after {{computed}}key '{{key}}'.",
310 extraValue: "Extra space before value for {{computed}}key '{{key}}'.",
311 missingKey: "Missing space after {{computed}}key '{{key}}'.",
312 missingValue: "Missing space before value for {{computed}}key '{{key}}'."
320 * "key-spacing": [2, {
321 * beforeColon: false,
323 * align: "colon" // Optional, or "value"
326 const options = context.options[0] || {},
327 ruleOptions = initOptions({}, options),
328 multiLineOptions = ruleOptions.multiLine,
329 singleLineOptions = ruleOptions.singleLine,
330 alignmentOptions = ruleOptions.align || null;
332 const sourceCode = context.getSourceCode();
335 * Checks whether a property is a member of the property group it follows.
336 * @param {ASTNode} lastMember The last Property known to be in the group.
337 * @param {ASTNode} candidate The next Property that might be in the group.
338 * @returns {boolean} True if the candidate property is part of the group.
340 function continuesPropertyGroup(lastMember, candidate) {
341 const groupEndLine = lastMember.loc.start.line,
342 candidateStartLine = candidate.loc.start.line;
344 if (candidateStartLine - groupEndLine <= 1) {
349 * Check that the first comment is adjacent to the end of the group, the
350 * last comment is adjacent to the candidate property, and that successive
351 * comments are adjacent to each other.
353 const leadingComments = sourceCode.getCommentsBefore(candidate);
356 leadingComments.length &&
357 leadingComments[0].loc.start.line - groupEndLine <= 1 &&
358 candidateStartLine - last(leadingComments).loc.end.line <= 1
360 for (let i = 1; i < leadingComments.length; i++) {
361 if (leadingComments[i].loc.start.line - leadingComments[i - 1].loc.end.line > 1) {
372 * Determines if the given property is key-value property.
373 * @param {ASTNode} property Property node to check.
374 * @returns {boolean} Whether the property is a key-value property.
376 function isKeyValueProperty(property) {
379 property.shorthand ||
380 property.kind !== "init" || property.type !== "Property") // Could be "ExperimentalSpreadProperty" or "SpreadElement"
385 * Starting from the given a node (a property.key node here) looks forward
386 * until it finds the last token before a colon punctuator and returns it.
387 * @param {ASTNode} node The node to start looking from.
388 * @returns {ASTNode} The last token before a colon punctuator.
390 function getLastTokenBeforeColon(node) {
391 const colonToken = sourceCode.getTokenAfter(node, astUtils.isColonToken);
393 return sourceCode.getTokenBefore(colonToken);
397 * Starting from the given a node (a property.key node here) looks forward
398 * until it finds the colon punctuator and returns it.
399 * @param {ASTNode} node The node to start looking from.
400 * @returns {ASTNode} The colon punctuator.
402 function getNextColon(node) {
403 return sourceCode.getTokenAfter(node, astUtils.isColonToken);
407 * Gets an object literal property's key as the identifier name or string value.
408 * @param {ASTNode} property Property node whose key to retrieve.
409 * @returns {string} The property's key.
411 function getKey(property) {
412 const key = property.key;
414 if (property.computed) {
415 return sourceCode.getText().slice(key.range[0], key.range[1]);
418 return property.key.name || property.key.value;
422 * Reports an appropriately-formatted error if spacing is incorrect on one
424 * @param {ASTNode} property Key-value pair in an object literal.
425 * @param {string} side Side being verified - either "key" or "value".
426 * @param {string} whitespace Actual whitespace string.
427 * @param {int} expected Expected whitespace length.
428 * @param {string} mode Value of the mode as "strict" or "minimum"
431 function report(property, side, whitespace, expected, mode) {
432 const diff = whitespace.length - expected,
433 nextColon = getNextColon(property.key),
434 tokenBeforeColon = sourceCode.getTokenBefore(nextColon, { includeComments: true }),
435 tokenAfterColon = sourceCode.getTokenAfter(nextColon, { includeComments: true }),
436 isKeySide = side === "key",
437 locStart = isKeySide ? tokenBeforeColon.loc.start : tokenAfterColon.loc.start,
439 diffAbs = Math.abs(diff),
440 spaces = Array(diffAbs + 1).join(" ");
443 diff && mode === "strict" ||
444 diff < 0 && mode === "minimum" ||
445 diff > 0 && !expected && mode === "minimum") &&
446 !(expected && containsLineTerminator(whitespace))
455 range = [tokenBeforeColon.range[1], tokenBeforeColon.range[1] + diffAbs];
457 range = [tokenAfterColon.range[0] - diffAbs, tokenAfterColon.range[0]];
459 fix = function(fixer) {
460 return fixer.removeRange(range);
466 fix = function(fixer) {
467 return fixer.insertTextAfter(tokenBeforeColon, spaces);
470 fix = function(fixer) {
471 return fixer.insertTextBefore(tokenAfterColon, spaces);
479 messageId = side === "key" ? "extraKey" : "extraValue";
481 messageId = side === "key" ? "missingKey" : "missingValue";
485 node: property[side],
489 computed: property.computed ? "computed " : "",
490 key: getKey(property)
498 * Gets the number of characters in a key, including quotes around string
499 * keys and braces around computed property keys.
500 * @param {ASTNode} property Property of on object literal.
501 * @returns {int} Width of the key.
503 function getKeyWidth(property) {
504 const startToken = sourceCode.getFirstToken(property);
505 const endToken = getLastTokenBeforeColon(property.key);
507 return endToken.range[1] - startToken.range[0];
511 * Gets the whitespace around the colon in an object literal property.
512 * @param {ASTNode} property Property node from an object literal.
513 * @returns {Object} Whitespace before and after the property's colon.
515 function getPropertyWhitespace(property) {
516 const whitespace = /(\s*):(\s*)/u.exec(sourceCode.getText().slice(
517 property.key.range[1], property.value.range[0]
522 beforeColon: whitespace[1],
523 afterColon: whitespace[2]
530 * Creates groups of properties.
531 * @param {ASTNode} node ObjectExpression node being evaluated.
532 * @returns {Array.<ASTNode[]>} Groups of property AST node lists.
534 function createGroups(node) {
535 if (node.properties.length === 1) {
536 return [node.properties];
539 return node.properties.reduce((groups, property) => {
540 const currentGroup = last(groups),
541 prev = last(currentGroup);
543 if (!prev || continuesPropertyGroup(prev, property)) {
544 currentGroup.push(property);
546 groups.push([property]);
556 * Verifies correct vertical alignment of a group of properties.
557 * @param {ASTNode[]} properties List of Property AST nodes.
560 function verifyGroupAlignment(properties) {
561 const length = properties.length,
562 widths = properties.map(getKeyWidth), // Width of keys, including quotes
563 align = alignmentOptions.on; // "value" or "colon"
564 let targetWidth = Math.max(...widths),
565 beforeColon, afterColon, mode;
567 if (alignmentOptions && length > 1) { // When aligning values within a group, use the alignment configuration.
568 beforeColon = alignmentOptions.beforeColon;
569 afterColon = alignmentOptions.afterColon;
570 mode = alignmentOptions.mode;
572 beforeColon = multiLineOptions.beforeColon;
573 afterColon = multiLineOptions.afterColon;
574 mode = alignmentOptions.mode;
577 // Conditionally include one space before or after colon
578 targetWidth += (align === "colon" ? beforeColon : afterColon);
580 for (let i = 0; i < length; i++) {
581 const property = properties[i];
582 const whitespace = getPropertyWhitespace(property);
584 if (whitespace) { // Object literal getters/setters lack a colon
585 const width = widths[i];
587 if (align === "value") {
588 report(property, "key", whitespace.beforeColon, beforeColon, mode);
589 report(property, "value", whitespace.afterColon, targetWidth - width, mode);
590 } else { // align = "colon"
591 report(property, "key", whitespace.beforeColon, targetWidth - width, mode);
592 report(property, "value", whitespace.afterColon, afterColon, mode);
599 * Verifies spacing of property conforms to specified options.
600 * @param {ASTNode} node Property node being evaluated.
601 * @param {Object} lineOptions Configured singleLine or multiLine options
604 function verifySpacing(node, lineOptions) {
605 const actual = getPropertyWhitespace(node);
607 if (actual) { // Object literal getters/setters lack colons
608 report(node, "key", actual.beforeColon, lineOptions.beforeColon, lineOptions.mode);
609 report(node, "value", actual.afterColon, lineOptions.afterColon, lineOptions.mode);
614 * Verifies spacing of each property in a list.
615 * @param {ASTNode[]} properties List of Property AST nodes.
616 * @param {Object} lineOptions Configured singleLine or multiLine options
619 function verifyListSpacing(properties, lineOptions) {
620 const length = properties.length;
622 for (let i = 0; i < length; i++) {
623 verifySpacing(properties[i], lineOptions);
628 * Verifies vertical alignment, taking into account groups of properties.
629 * @param {ASTNode} node ObjectExpression node being evaluated.
632 function verifyAlignment(node) {
633 createGroups(node).forEach(group => {
634 const properties = group.filter(isKeyValueProperty);
636 if (properties.length > 0 && isSingleLineProperties(properties)) {
637 verifyListSpacing(properties, multiLineOptions);
639 verifyGroupAlignment(properties);
644 //--------------------------------------------------------------------------
646 //--------------------------------------------------------------------------
648 if (alignmentOptions) { // Verify vertical alignment
651 ObjectExpression(node) {
652 if (isSingleLine(node)) {
653 verifyListSpacing(node.properties.filter(isKeyValueProperty), singleLineOptions);
655 verifyAlignment(node);
662 // Obey beforeColon and afterColon in each property as configured
665 verifySpacing(node, isSingleLine(node.parent) ? singleLineOptions : multiLineOptions);