408 lines
13 KiB
JavaScript
408 lines
13 KiB
JavaScript
/**
|
|
* @fileoverview Rule to flag statements without curly braces
|
|
* @author Nicholas C. Zakas
|
|
*/
|
|
'use strict';
|
|
|
|
//------------------------------------------------------------------------------
|
|
// Requirements
|
|
//------------------------------------------------------------------------------
|
|
|
|
const astUtils = require('./utils/ast-utils');
|
|
|
|
//------------------------------------------------------------------------------
|
|
// Rule Definition
|
|
//------------------------------------------------------------------------------
|
|
|
|
/** @type {import('../types').Rule.RuleModule} */
|
|
module.exports = {
|
|
meta: {
|
|
type: 'suggestion',
|
|
|
|
docs: {
|
|
description: 'Enforce consistent brace style for all control statements',
|
|
recommended: false,
|
|
frozen: true,
|
|
url: 'https://eslint.org/docs/latest/rules/curly',
|
|
},
|
|
|
|
schema: {
|
|
anyOf: [
|
|
{
|
|
type: 'array',
|
|
items: [
|
|
{
|
|
enum: ['all'],
|
|
},
|
|
],
|
|
minItems: 0,
|
|
maxItems: 1,
|
|
},
|
|
{
|
|
type: 'array',
|
|
items: [
|
|
{
|
|
enum: ['multi', 'multi-line', 'multi-or-nest'],
|
|
},
|
|
{
|
|
enum: ['consistent'],
|
|
},
|
|
],
|
|
minItems: 0,
|
|
maxItems: 2,
|
|
},
|
|
],
|
|
},
|
|
|
|
defaultOptions: ['all'],
|
|
|
|
fixable: 'code',
|
|
|
|
messages: {
|
|
missingCurlyAfter: "Expected { after '{{name}}'.",
|
|
missingCurlyAfterCondition: "Expected { after '{{name}}' condition.",
|
|
unexpectedCurlyAfter: "Unnecessary { after '{{name}}'.",
|
|
unexpectedCurlyAfterCondition:
|
|
"Unnecessary { after '{{name}}' condition.",
|
|
},
|
|
},
|
|
|
|
create(context) {
|
|
const multiOnly = context.options[0] === 'multi';
|
|
const multiLine = context.options[0] === 'multi-line';
|
|
const multiOrNest = context.options[0] === 'multi-or-nest';
|
|
const consistent = context.options[1] === 'consistent';
|
|
|
|
const sourceCode = context.sourceCode;
|
|
|
|
//--------------------------------------------------------------------------
|
|
// Helpers
|
|
//--------------------------------------------------------------------------
|
|
|
|
/**
|
|
* Determines if a given node is a one-liner that's on the same line as it's preceding code.
|
|
* @param {ASTNode} node The node to check.
|
|
* @returns {boolean} True if the node is a one-liner that's on the same line as it's preceding code.
|
|
* @private
|
|
*/
|
|
function isCollapsedOneLiner(node) {
|
|
const before = sourceCode.getTokenBefore(node);
|
|
const last = sourceCode.getLastToken(node);
|
|
const lastExcludingSemicolon =
|
|
astUtils.isSemicolonToken(last) ?
|
|
sourceCode.getTokenBefore(last)
|
|
: last;
|
|
|
|
return before.loc.start.line === lastExcludingSemicolon.loc.end.line;
|
|
}
|
|
|
|
/**
|
|
* Determines if a given node is a one-liner.
|
|
* @param {ASTNode} node The node to check.
|
|
* @returns {boolean} True if the node is a one-liner.
|
|
* @private
|
|
*/
|
|
function isOneLiner(node) {
|
|
if (node.type === 'EmptyStatement') {
|
|
return true;
|
|
}
|
|
|
|
const first = sourceCode.getFirstToken(node);
|
|
const last = sourceCode.getLastToken(node);
|
|
const lastExcludingSemicolon =
|
|
astUtils.isSemicolonToken(last) ?
|
|
sourceCode.getTokenBefore(last)
|
|
: last;
|
|
|
|
return first.loc.start.line === lastExcludingSemicolon.loc.end.line;
|
|
}
|
|
|
|
/**
|
|
* Determines if a semicolon needs to be inserted after removing a set of curly brackets, in order to avoid a SyntaxError.
|
|
* @param {Token} closingBracket The } token
|
|
* @returns {boolean} `true` if a semicolon needs to be inserted after the last statement in the block.
|
|
*/
|
|
function needsSemicolon(closingBracket) {
|
|
const tokenBefore = sourceCode.getTokenBefore(closingBracket);
|
|
const tokenAfter = sourceCode.getTokenAfter(closingBracket);
|
|
const lastBlockNode = sourceCode.getNodeByRangeIndex(
|
|
tokenBefore.range[0]
|
|
);
|
|
|
|
if (astUtils.isSemicolonToken(tokenBefore)) {
|
|
// If the last statement already has a semicolon, don't add another one.
|
|
return false;
|
|
}
|
|
|
|
if (!tokenAfter) {
|
|
// If there are no statements after this block, there is no need to add a semicolon.
|
|
return false;
|
|
}
|
|
|
|
if (
|
|
lastBlockNode.type === 'BlockStatement' &&
|
|
lastBlockNode.parent.type !== 'FunctionExpression' &&
|
|
lastBlockNode.parent.type !== 'ArrowFunctionExpression'
|
|
) {
|
|
/*
|
|
* If the last node surrounded by curly brackets is a BlockStatement (other than a FunctionExpression or an ArrowFunctionExpression),
|
|
* don't insert a semicolon. Otherwise, the semicolon would be parsed as a separate statement, which would cause
|
|
* a SyntaxError if it was followed by `else`.
|
|
*/
|
|
return false;
|
|
}
|
|
|
|
if (tokenBefore.loc.end.line === tokenAfter.loc.start.line) {
|
|
// If the next token is on the same line, insert a semicolon.
|
|
return true;
|
|
}
|
|
|
|
if (/^[([/`+-]/u.test(tokenAfter.value)) {
|
|
// If the next token starts with a character that would disrupt ASI, insert a semicolon.
|
|
return true;
|
|
}
|
|
|
|
if (
|
|
tokenBefore.type === 'Punctuator' &&
|
|
(tokenBefore.value === '++' || tokenBefore.value === '--')
|
|
) {
|
|
// If the last token is ++ or --, insert a semicolon to avoid disrupting ASI.
|
|
return true;
|
|
}
|
|
|
|
// Otherwise, do not insert a semicolon.
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* Prepares to check the body of a node to see if it's a block statement.
|
|
* @param {ASTNode} node The node to report if there's a problem.
|
|
* @param {ASTNode} body The body node to check for blocks.
|
|
* @param {string} name The name to report if there's a problem.
|
|
* @param {{ condition: boolean }} opts Options to pass to the report functions
|
|
* @returns {Object} a prepared check object, with "actual", "expected", "check" properties.
|
|
* "actual" will be `true` or `false` whether the body is already a block statement.
|
|
* "expected" will be `true` or `false` if the body should be a block statement or not, or
|
|
* `null` if it doesn't matter, depending on the rule options. It can be modified to change
|
|
* the final behavior of "check".
|
|
* "check" will be a function reporting appropriate problems depending on the other
|
|
* properties.
|
|
*/
|
|
function prepareCheck(node, body, name, opts) {
|
|
const hasBlock = body.type === 'BlockStatement';
|
|
let expected = null;
|
|
|
|
if (
|
|
hasBlock &&
|
|
(body.body.length !== 1 ||
|
|
astUtils.areBracesNecessary(body, sourceCode))
|
|
) {
|
|
expected = true;
|
|
} else if (multiOnly) {
|
|
expected = false;
|
|
} else if (multiLine) {
|
|
if (!isCollapsedOneLiner(body)) {
|
|
expected = true;
|
|
}
|
|
|
|
// otherwise, the body is allowed to have braces or not to have braces
|
|
} else if (multiOrNest) {
|
|
if (hasBlock) {
|
|
const statement = body.body[0];
|
|
const leadingCommentsInBlock =
|
|
sourceCode.getCommentsBefore(statement);
|
|
|
|
expected =
|
|
!isOneLiner(statement) || leadingCommentsInBlock.length > 0;
|
|
} else {
|
|
expected = !isOneLiner(body);
|
|
}
|
|
} else {
|
|
// default "all"
|
|
expected = true;
|
|
}
|
|
|
|
return {
|
|
actual: hasBlock,
|
|
expected,
|
|
check() {
|
|
if (this.expected !== null && this.expected !== this.actual) {
|
|
if (this.expected) {
|
|
context.report({
|
|
node,
|
|
loc: body.loc,
|
|
messageId:
|
|
opts && opts.condition ?
|
|
'missingCurlyAfterCondition'
|
|
: 'missingCurlyAfter',
|
|
data: {
|
|
name,
|
|
},
|
|
fix: (fixer) =>
|
|
fixer.replaceText(body, `{${sourceCode.getText(body)}}`),
|
|
});
|
|
} else {
|
|
context.report({
|
|
node,
|
|
loc: body.loc,
|
|
messageId:
|
|
opts && opts.condition ?
|
|
'unexpectedCurlyAfterCondition'
|
|
: 'unexpectedCurlyAfter',
|
|
data: {
|
|
name,
|
|
},
|
|
fix(fixer) {
|
|
/*
|
|
* `do while` expressions sometimes need a space to be inserted after `do`.
|
|
* e.g. `do{foo()} while (bar)` should be corrected to `do foo() while (bar)`
|
|
*/
|
|
const needsPrecedingSpace =
|
|
node.type === 'DoWhileStatement' &&
|
|
sourceCode.getTokenBefore(body).range[1] ===
|
|
body.range[0] &&
|
|
!astUtils.canTokensBeAdjacent(
|
|
'do',
|
|
sourceCode.getFirstToken(body, {
|
|
skip: 1,
|
|
})
|
|
);
|
|
|
|
const openingBracket = sourceCode.getFirstToken(body);
|
|
const closingBracket = sourceCode.getLastToken(body);
|
|
const lastTokenInBlock =
|
|
sourceCode.getTokenBefore(closingBracket);
|
|
|
|
if (needsSemicolon(closingBracket)) {
|
|
/*
|
|
* If removing braces would cause a SyntaxError due to multiple statements on the same line (or
|
|
* change the semantics of the code due to ASI), don't perform a fix.
|
|
*/
|
|
return null;
|
|
}
|
|
|
|
const resultingBodyText =
|
|
sourceCode
|
|
.getText()
|
|
.slice(
|
|
openingBracket.range[1],
|
|
lastTokenInBlock.range[0]
|
|
) +
|
|
sourceCode.getText(lastTokenInBlock) +
|
|
sourceCode
|
|
.getText()
|
|
.slice(
|
|
lastTokenInBlock.range[1],
|
|
closingBracket.range[0]
|
|
);
|
|
|
|
return fixer.replaceText(
|
|
body,
|
|
(needsPrecedingSpace ? ' ' : '') + resultingBodyText
|
|
);
|
|
},
|
|
});
|
|
}
|
|
}
|
|
},
|
|
};
|
|
}
|
|
|
|
/**
|
|
* Prepares to check the bodies of a "if", "else if" and "else" chain.
|
|
* @param {ASTNode} node The first IfStatement node of the chain.
|
|
* @returns {Object[]} prepared checks for each body of the chain. See `prepareCheck` for more
|
|
* information.
|
|
*/
|
|
function prepareIfChecks(node) {
|
|
const preparedChecks = [];
|
|
|
|
for (
|
|
let currentNode = node;
|
|
currentNode;
|
|
currentNode = currentNode.alternate
|
|
) {
|
|
preparedChecks.push(
|
|
prepareCheck(currentNode, currentNode.consequent, 'if', {
|
|
condition: true,
|
|
})
|
|
);
|
|
if (
|
|
currentNode.alternate &&
|
|
currentNode.alternate.type !== 'IfStatement'
|
|
) {
|
|
preparedChecks.push(
|
|
prepareCheck(currentNode, currentNode.alternate, 'else')
|
|
);
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (consistent) {
|
|
/*
|
|
* If any node should have or already have braces, make sure they
|
|
* all have braces.
|
|
* If all nodes shouldn't have braces, make sure they don't.
|
|
*/
|
|
const expected = preparedChecks.some((preparedCheck) => {
|
|
if (preparedCheck.expected !== null) {
|
|
return preparedCheck.expected;
|
|
}
|
|
return preparedCheck.actual;
|
|
});
|
|
|
|
preparedChecks.forEach((preparedCheck) => {
|
|
preparedCheck.expected = expected;
|
|
});
|
|
}
|
|
|
|
return preparedChecks;
|
|
}
|
|
|
|
//--------------------------------------------------------------------------
|
|
// Public
|
|
//--------------------------------------------------------------------------
|
|
|
|
return {
|
|
IfStatement(node) {
|
|
const parent = node.parent;
|
|
const isElseIf =
|
|
parent.type === 'IfStatement' && parent.alternate === node;
|
|
|
|
if (!isElseIf) {
|
|
// This is a top `if`, check the whole `if-else-if` chain
|
|
prepareIfChecks(node).forEach((preparedCheck) => {
|
|
preparedCheck.check();
|
|
});
|
|
}
|
|
|
|
// Skip `else if`, it's already checked (when the top `if` was visited)
|
|
},
|
|
|
|
WhileStatement(node) {
|
|
prepareCheck(node, node.body, 'while', {
|
|
condition: true,
|
|
}).check();
|
|
},
|
|
|
|
DoWhileStatement(node) {
|
|
prepareCheck(node, node.body, 'do').check();
|
|
},
|
|
|
|
ForStatement(node) {
|
|
prepareCheck(node, node.body, 'for', {
|
|
condition: true,
|
|
}).check();
|
|
},
|
|
|
|
ForInStatement(node) {
|
|
prepareCheck(node, node.body, 'for-in').check();
|
|
},
|
|
|
|
ForOfStatement(node) {
|
|
prepareCheck(node, node.body, 'for-of').check();
|
|
},
|
|
};
|
|
},
|
|
};
|