/**
* @fileoverview Rule to specify spacing of object literal keys and values
* @author Brandon Mills
*/
"use strict";
//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------
const astUtils = require("../ast-utils");
//------------------------------------------------------------------------------
// Helpers
//------------------------------------------------------------------------------
/**
* Checks whether a string contains a line terminator as defined in
* http://www.ecma-international.org/ecma-262/5.1/#sec-7.3
* @param {string} str String to test.
* @returns {boolean} True if str contains a line terminator.
*/
function containsLineTerminator(str) {
return astUtils.LINEBREAK_MATCHER.test(str);
}
/**
* Gets the last element of an array.
* @param {Array} arr An array.
* @returns {any} Last element of arr.
*/
function last(arr) {
return arr[arr.length - 1];
}
/**
* Checks whether a node is contained on a single line.
* @param {ASTNode} node AST Node being evaluated.
* @returns {boolean} True if the node is a single line.
*/
function isSingleLine(node) {
return (node.loc.end.line === node.loc.start.line);
}
/**
* Initializes a single option property from the configuration with defaults for undefined values
* @param {Object} toOptions Object to be initialized
* @param {Object} fromOptions Object to be initialized from
* @returns {Object} The object with correctly initialized options and values
*/
function initOptionProperty(toOptions, fromOptions) {
toOptions.mode = fromOptions.mode || "strict";
// Set value of beforeColon
if (typeof fromOptions.beforeColon !== "undefined") {
toOptions.beforeColon = +fromOptions.beforeColon;
} else {
toOptions.beforeColon = 0;
}
// Set value of afterColon
if (typeof fromOptions.afterColon !== "undefined") {
toOptions.afterColon = +fromOptions.afterColon;
} else {
toOptions.afterColon = 1;
}
// Set align if exists
if (typeof fromOptions.align !== "undefined") {
if (typeof fromOptions.align === "object") {
toOptions.align = fromOptions.align;
} else { // "string"
toOptions.align = {
on: fromOptions.align,
mode: toOptions.mode,
beforeColon: toOptions.beforeColon,
afterColon: toOptions.afterColon
};
}
}
return toOptions;
}
/**
* Initializes all the option values (singleLine, multiLine and align) from the configuration with defaults for undefined values
* @param {Object} toOptions Object to be initialized
* @param {Object} fromOptions Object to be initialized from
* @returns {Object} The object with correctly initialized options and values
*/
function initOptions(toOptions, fromOptions) {
if (typeof fromOptions.align === "object") {
// Initialize the alignment configuration
toOptions.align = initOptionProperty({}, fromOptions.align);
toOptions.align.on = fromOptions.align.on || "colon";
toOptions.align.mode = fromOptions.align.mode || "strict";
toOptions.multiLine = initOptionProperty({}, (fromOptions.multiLine || fromOptions));
toOptions.singleLine = initOptionProperty({}, (fromOptions.singleLine || fromOptions));
} else { // string or undefined
toOptions.multiLine = initOptionProperty({}, (fromOptions.multiLine || fromOptions));
toOptions.singleLine = initOptionProperty({}, (fromOptions.singleLine || fromOptions));
// If alignment options are defined in multiLine, pull them out into the general align configuration
if (toOptions.multiLine.align) {
toOptions.align = {
on: toOptions.multiLine.align.on,
mode: toOptions.multiLine.align.mode || toOptions.multiLine.mode,
beforeColon: toOptions.multiLine.align.beforeColon,
afterColon: toOptions.multiLine.align.afterColon
};
}
}
return toOptions;
}
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
const messages = {
key: "{{error}} space after {{computed}}key '{{key}}'.",
value: "{{error}} space before value for {{computed}}key '{{key}}'."
};
module.exports = {
meta: {
docs: {
description: "enforce consistent spacing between keys and values in object literal properties",
category: "Stylistic Issues",
recommended: false,
url: "https://eslint.org/docs/rules/key-spacing"
},
fixable: "whitespace",
schema: [{
anyOf: [
{
type: "object",
properties: {
align: {
anyOf: [
{
enum: ["colon", "value"]
},
{
type: "object",
properties: {
mode: {
enum: ["strict", "minimum"]
},
on: {
enum: ["colon", "value"]
},
beforeColon: {
type: "boolean"
},
afterColon: {
type: "boolean"
}
},
additionalProperties: false
}
]
},
mode: {
enum: ["strict", "minimum"]
},
beforeColon: {
type: "boolean"
},
afterColon: {
type: "boolean"
}
},
additionalProperties: false
},
{
type: "object",
properties: {
singleLine: {
type: "object",
properties: {
mode: {
enum: ["strict", "minimum"]
},
beforeColon: {
type: "boolean"
},
afterColon: {
type: "boolean"
}
},
additionalProperties: false
},
multiLine: {
type: "object",
properties: {
align: {
anyOf: [
{
enum: ["colon", "value"]
},
{
type: "object",
properties: {
mode: {
enum: ["strict", "minimum"]
},
on: {
enum: ["colon", "value"]
},
beforeColon: {
type: "boolean"
},
afterColon: {
type: "boolean"
}
},
additionalProperties: false
}
]
},
mode: {
enum: ["strict", "minimum"]
},
beforeColon: {
type: "boolean"
},
afterColon: {
type: "boolean"
}
},
additionalProperties: false
}
},
additionalProperties: false
},
{
type: "object",
properties: {
singleLine: {
type: "object",
properties: {
mode: {
enum: ["strict", "minimum"]
},
beforeColon: {
type: "boolean"
},
afterColon: {
type: "boolean"
}
},
additionalProperties: false
},
multiLine: {
type: "object",
properties: {
mode: {
enum: ["strict", "minimum"]
},
beforeColon: {
type: "boolean"
},
afterColon: {
type: "boolean"
}
},
additionalProperties: false
},
align: {
type: "object",
properties: {
mode: {
enum: ["strict", "minimum"]
},
on: {
enum: ["colon", "value"]
},
beforeColon: {
type: "boolean"
},
afterColon: {
type: "boolean"
}
},
additionalProperties: false
}
},
additionalProperties: false
}
]
}]
},
create(context) {
/**
* OPTIONS
* "key-spacing": [2, {
* beforeColon: false,
* afterColon: true,
* align: "colon" // Optional, or "value"
* }
*/
const options = context.options[0] || {},
ruleOptions = initOptions({}, options),
multiLineOptions = ruleOptions.multiLine,
singleLineOptions = ruleOptions.singleLine,
alignmentOptions = ruleOptions.align || null;
const sourceCode = context.getSourceCode();
/**
* Checks whether a property is a member of the property group it follows.
* @param {ASTNode} lastMember The last Property known to be in the group.
* @param {ASTNode} candidate The next Property that might be in the group.
* @returns {boolean} True if the candidate property is part of the group.
*/
function continuesPropertyGroup(lastMember, candidate) {
const groupEndLine = lastMember.loc.start.line,
candidateStartLine = candidate.loc.start.line;
if (candidateStartLine - groupEndLine <= 1) {
return true;
}
/*
* Check that the first comment is adjacent to the end of the group, the
* last comment is adjacent to the candidate property, and that successive
* comments are adjacent to each other.
*/
const leadingComments = sourceCode.getCommentsBefore(candidate);
if (
leadingComments.length &&
leadingComments[0].loc.start.line - groupEndLine <= 1 &&
candidateStartLine - last(leadingComments).loc.end.line <= 1
) {
for (let i = 1; i < leadingComments.length; i++) {
if (leadingComments[i].loc.start.line - leadingComments[i - 1].loc.end.line > 1) {
return false;
}
}
return true;
}
return false;
}
/**
* Determines if the given property is key-value property.
* @param {ASTNode} property Property node to check.
* @returns {boolean} Whether the property is a key-value property.
*/
function isKeyValueProperty(property) {
return !(
(property.method ||
property.shorthand ||
property.kind !== "init" || property.type !== "Property") // Could be "ExperimentalSpreadProperty" or "SpreadProperty"
);
}
/**
* Starting from the given a node (a property.key node here) looks forward
* until it finds the last token before a colon punctuator and returns it.
* @param {ASTNode} node The node to start looking from.
* @returns {ASTNode} The last token before a colon punctuator.
*/
function getLastTokenBeforeColon(node) {
const colonToken = sourceCode.getTokenAfter(node, astUtils.isColonToken);
return sourceCode.getTokenBefore(colonToken);
}
/**
* Starting from the given a node (a property.key node here) looks forward
* until it finds the colon punctuator and returns it.
* @param {ASTNode} node The node to start looking from.
* @returns {ASTNode} The colon punctuator.
*/
function getNextColon(node) {
return sourceCode.getTokenAfter(node, astUtils.isColonToken);
}
/**
* Gets an object literal property's key as the identifier name or string value.
* @param {ASTNode} property Property node whose key to retrieve.
* @returns {string} The property's key.
*/
function getKey(property) {
const key = property.key;
if (property.computed) {
return sourceCode.getText().slice(key.range[0], key.range[1]);
}
return property.key.name || property.key.value;
}
/**
* Reports an appropriately-formatted error if spacing is incorrect on one
* side of the colon.
* @param {ASTNode} property Key-value pair in an object literal.
* @param {string} side Side being verified - either "key" or "value".
* @param {string} whitespace Actual whitespace string.
* @param {int} expected Expected whitespace length.
* @param {string} mode Value of the mode as "strict" or "minimum"
* @returns {void}
*/
function report(property, side, whitespace, expected, mode) {
const diff = whitespace.length - expected,
nextColon = getNextColon(property.key),
tokenBeforeColon = sourceCode.getTokenBefore(nextColon, { includeComments: true }),
tokenAfterColon = sourceCode.getTokenAfter(nextColon, { includeComments: true }),
isKeySide = side === "key",
locStart = isKeySide ? tokenBeforeColon.loc.start : tokenAfterColon.loc.start,
isExtra = diff > 0,
diffAbs = Math.abs(diff),
spaces = Array(diffAbs + 1).join(" ");
if ((
diff && mode === "strict" ||
diff < 0 && mode === "minimum" ||
diff > 0 && !expected && mode === "minimum") &&
!(expected && containsLineTerminator(whitespace))
) {
let fix;
if (isExtra) {
let range;
// Remove whitespace
if (isKeySide) {
range = [tokenBeforeColon.range[1], tokenBeforeColon.range[1] + diffAbs];
} else {
range = [tokenAfterColon.range[0] - diffAbs, tokenAfterColon.range[0]];
}
fix = function(fixer) {
return fixer.removeRange(range);
};
} else {
// Add whitespace
if (isKeySide) {
fix = function(fixer) {
return fixer.insertTextAfter(tokenBeforeColon, spaces);
};
} else {
fix = function(fixer) {
return fixer.insertTextBefore(tokenAfterColon, spaces);
};
}
}
context.report({
node: property[side],
loc: locStart,
message: messages[side],
data: {
error: isExtra ? "Extra" : "Missing",
computed: property.computed ? "computed " : "",
key: getKey(property)
},
fix
});
}
}
/**
* Gets the number of characters in a key, including quotes around string
* keys and braces around computed property keys.
* @param {ASTNode} property Property of on object literal.
* @returns {int} Width of the key.
*/
function getKeyWidth(property) {
const startToken = sourceCode.getFirstToken(property);
const endToken = getLastTokenBeforeColon(property.key);
return endToken.range[1] - startToken.range[0];
}
/**
* Gets the whitespace around the colon in an object literal property.
* @param {ASTNode} property Property node from an object literal.
* @returns {Object} Whitespace before and after the property's colon.
*/
function getPropertyWhitespace(property) {
const whitespace = /(\s*):(\s*)/.exec(sourceCode.getText().slice(
property.key.range[1], property.value.range[0]
));
if (whitespace) {
return {
beforeColon: whitespace[1],
afterColon: whitespace[2]
};
}
return null;
}
/**
* Creates groups of properties.
* @param {ASTNode} node ObjectExpression node being evaluated.
* @returns {Array.<ASTNode[]>} Groups of property AST node lists.
*/
function createGroups(node) {
if (node.properties.length === 1) {
return [node.properties];
}
return node.properties.reduce((groups, property) => {
const currentGroup = last(groups),
prev = last(currentGroup);
if (!prev || continuesPropertyGroup(prev, property)) {
currentGroup.push(property);
} else {
groups.push([property]);
}
return groups;
}, [
[]
]);
}
/**
* Verifies correct vertical alignment of a group of properties.
* @param {ASTNode[]} properties List of Property AST nodes.
* @returns {void}
*/
function verifyGroupAlignment(properties) {
const length = properties.length,
widths = properties.map(getKeyWidth), // Width of keys, including quotes
align = alignmentOptions.on; // "value" or "colon"
let targetWidth = Math.max.apply(null, widths),
beforeColon, afterColon, mode;
if (alignmentOptions && length > 1) { // When aligning values within a group, use the alignment configuration.
beforeColon = alignmentOptions.beforeColon;
afterColon = alignmentOptions.afterColon;
mode = alignmentOptions.mode;
} else {
beforeColon = multiLineOptions.beforeColon;
afterColon = multiLineOptions.afterColon;
mode = alignmentOptions.mode;
}
// Conditionally include one space before or after colon
targetWidth += (align === "colon" ? beforeColon : afterColon);
for (let i = 0; i < length; i++) {
const property = properties[i];
const whitespace = getPropertyWhitespace(property);
if (whitespace) { // Object literal getters/setters lack a colon
const width = widths[i];
if (align === "value") {
report(property, "key", whitespace.beforeColon, beforeColon, mode);
report(property, "value", whitespace.afterColon, targetWidth - width, mode);
} else { // align = "colon"
report(property, "key", whitespace.beforeColon, targetWidth - width, mode);
report(property, "value", whitespace.afterColon, afterColon, mode);
}
}
}
}
/**
* Verifies vertical alignment, taking into account groups of properties.
* @param {ASTNode} node ObjectExpression node being evaluated.
* @returns {void}
*/
function verifyAlignment(node) {
createGroups(node).forEach(group => {
verifyGroupAlignment(group.filter(isKeyValueProperty));
});
}
/**
* Verifies spacing of property conforms to specified options.
* @param {ASTNode} node Property node being evaluated.
* @param {Object} lineOptions Configured singleLine or multiLine options
* @returns {void}
*/
function verifySpacing(node, lineOptions) {
const actual = getPropertyWhitespace(node);
if (actual) { // Object literal getters/setters lack colons
report(node, "key", actual.beforeColon, lineOptions.beforeColon, lineOptions.mode);
report(node, "value", actual.afterColon, lineOptions.afterColon, lineOptions.mode);
}
}
/**
* Verifies spacing of each property in a list.
* @param {ASTNode[]} properties List of Property AST nodes.
* @returns {void}
*/
function verifyListSpacing(properties) {
const length = properties.length;
for (let i = 0; i < length; i++) {
verifySpacing(properties[i], singleLineOptions);
}
}
//--------------------------------------------------------------------------
// Public API
//--------------------------------------------------------------------------
if (alignmentOptions) { // Verify vertical alignment
return {
ObjectExpression(node) {
if (isSingleLine(node)) {
verifyListSpacing(node.properties.filter(isKeyValueProperty));
} else {
verifyAlignment(node);
}
}
};
}
// Obey beforeColon and afterColon in each property as configured
return {
Property(node) {
verifySpacing(node, isSingleLine(node.parent) ? singleLineOptions : multiLineOptions);
}
};
}
};