/**
* @fileoverview Rule to enforce linebreaks after open and before close array brackets
* @author Jan Peer Stöcklmair <https://github.com/JPeer264>
*/
"use strict";
const astUtils = require("../ast-utils");
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
module.exports = {
meta: {
docs: {
description: "enforce linebreaks after opening and before closing array brackets",
category: "Stylistic Issues",
recommended: false,
url: "https://eslint.org/docs/rules/array-bracket-newline"
},
fixable: "whitespace",
schema: [
{
oneOf: [
{
enum: ["always", "never", "consistent"]
},
{
type: "object",
properties: {
multiline: {
type: "boolean"
},
minItems: {
type: ["integer", "null"],
minimum: 0
}
},
additionalProperties: false
}
]
}
]
},
create(context) {
const sourceCode = context.getSourceCode();
//----------------------------------------------------------------------
// Helpers
//----------------------------------------------------------------------
/**
* Normalizes a given option value.
*
* @param {string|Object|undefined} option - An option value to parse.
* @returns {{multiline: boolean, minItems: number}} Normalized option object.
*/
function normalizeOptionValue(option) {
let consistent = false;
let multiline = false;
let minItems = 0;
if (option) {
if (option === "consistent") {
consistent = true;
minItems = Number.POSITIVE_INFINITY;
} else if (option === "always" || option.minItems === 0) {
minItems = 0;
} else if (option === "never") {
minItems = Number.POSITIVE_INFINITY;
} else {
multiline = Boolean(option.multiline);
minItems = option.minItems || Number.POSITIVE_INFINITY;
}
} else {
consistent = false;
multiline = true;
minItems = Number.POSITIVE_INFINITY;
}
return { consistent, multiline, minItems };
}
/**
* Normalizes a given option value.
*
* @param {string|Object|undefined} options - An option value to parse.
* @returns {{ArrayExpression: {multiline: boolean, minItems: number}, ArrayPattern: {multiline: boolean, minItems: number}}} Normalized option object.
*/
function normalizeOptions(options) {
const value = normalizeOptionValue(options);
return { ArrayExpression: value, ArrayPattern: value };
}
/**
* Reports that there shouldn't be a linebreak after the first token
* @param {ASTNode} node - The node to report in the event of an error.
* @param {Token} token - The token to use for the report.
* @returns {void}
*/
function reportNoBeginningLinebreak(node, token) {
context.report({
node,
loc: token.loc,
message: "There should be no linebreak after '['.",
fix(fixer) {
const nextToken = sourceCode.getTokenAfter(token, { includeComments: true });
if (astUtils.isCommentToken(nextToken)) {
return null;
}
return fixer.removeRange([token.range[1], nextToken.range[0]]);
}
});
}
/**
* Reports that there shouldn't be a linebreak before the last token
* @param {ASTNode} node - The node to report in the event of an error.
* @param {Token} token - The token to use for the report.
* @returns {void}
*/
function reportNoEndingLinebreak(node, token) {
context.report({
node,
loc: token.loc,
message: "There should be no linebreak before ']'.",
fix(fixer) {
const previousToken = sourceCode.getTokenBefore(token, { includeComments: true });
if (astUtils.isCommentToken(previousToken)) {
return null;
}
return fixer.removeRange([previousToken.range[1], token.range[0]]);
}
});
}
/**
* Reports that there should be a linebreak after the first token
* @param {ASTNode} node - The node to report in the event of an error.
* @param {Token} token - The token to use for the report.
* @returns {void}
*/
function reportRequiredBeginningLinebreak(node, token) {
context.report({
node,
loc: token.loc,
message: "A linebreak is required after '['.",
fix(fixer) {
return fixer.insertTextAfter(token, "\n");
}
});
}
/**
* Reports that there should be a linebreak before the last token
* @param {ASTNode} node - The node to report in the event of an error.
* @param {Token} token - The token to use for the report.
* @returns {void}
*/
function reportRequiredEndingLinebreak(node, token) {
context.report({
node,
loc: token.loc,
message: "A linebreak is required before ']'.",
fix(fixer) {
return fixer.insertTextBefore(token, "\n");
}
});
}
/**
* Reports a given node if it violated this rule.
*
* @param {ASTNode} node - A node to check. This is an ArrayExpression node or an ArrayPattern node.
* @returns {void}
*/
function check(node) {
const elements = node.elements;
const normalizedOptions = normalizeOptions(context.options[0]);
const options = normalizedOptions[node.type];
const openBracket = sourceCode.getFirstToken(node);
const closeBracket = sourceCode.getLastToken(node);
const firstIncComment = sourceCode.getTokenAfter(openBracket, { includeComments: true });
const lastIncComment = sourceCode.getTokenBefore(closeBracket, { includeComments: true });
const first = sourceCode.getTokenAfter(openBracket);
const last = sourceCode.getTokenBefore(closeBracket);
const needsLinebreaks = (
elements.length >= options.minItems ||
(
options.multiline &&
elements.length > 0 &&
firstIncComment.loc.start.line !== lastIncComment.loc.end.line
) ||
(
elements.length === 0 &&
firstIncComment.type === "Block" &&
firstIncComment.loc.start.line !== lastIncComment.loc.end.line &&
firstIncComment === lastIncComment
) ||
(
options.consistent &&
firstIncComment.loc.start.line !== openBracket.loc.end.line
)
);
/*
* Use tokens or comments to check multiline or not.
* But use only tokens to check whether linebreaks are needed.
* This allows:
* var arr = [ // eslint-disable-line foo
* 'a'
* ]
*/
if (needsLinebreaks) {
if (astUtils.isTokenOnSameLine(openBracket, first)) {
reportRequiredBeginningLinebreak(node, openBracket);
}
if (astUtils.isTokenOnSameLine(last, closeBracket)) {
reportRequiredEndingLinebreak(node, closeBracket);
}
} else {
if (!astUtils.isTokenOnSameLine(openBracket, first)) {
reportNoBeginningLinebreak(node, openBracket);
}
if (!astUtils.isTokenOnSameLine(last, closeBracket)) {
reportNoEndingLinebreak(node, closeBracket);
}
}
}
//----------------------------------------------------------------------
// Public
//----------------------------------------------------------------------
return {
ArrayPattern: check,
ArrayExpression: check
};
}
};