Current File : /var/www/html/node_modules/eslint/lib/rules/semi.js
/**
* @fileoverview Rule to flag missing semicolons.
* @author Nicholas C. Zakas
*/
"use strict";
//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------
const FixTracker = require("./utils/fix-tracker");
const astUtils = require("./utils/ast-utils");
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
/** @type {import('../shared/types').Rule} */
module.exports = {
meta: {
type: "layout",
docs: {
description: "require or disallow semicolons instead of ASI",
recommended: false,
url: "https://eslint.org/docs/rules/semi"
},
fixable: "code",
schema: {
anyOf: [
{
type: "array",
items: [
{
enum: ["never"]
},
{
type: "object",
properties: {
beforeStatementContinuationChars: {
enum: ["always", "any", "never"]
}
},
additionalProperties: false
}
],
minItems: 0,
maxItems: 2
},
{
type: "array",
items: [
{
enum: ["always"]
},
{
type: "object",
properties: {
omitLastInOneLineBlock: { type: "boolean" }
},
additionalProperties: false
}
],
minItems: 0,
maxItems: 2
}
]
},
messages: {
missingSemi: "Missing semicolon.",
extraSemi: "Extra semicolon."
}
},
create(context) {
const OPT_OUT_PATTERN = /^[-[(/+`]/u; // One of [(/+-`
const unsafeClassFieldNames = new Set(["get", "set", "static"]);
const unsafeClassFieldFollowers = new Set(["*", "in", "instanceof"]);
const options = context.options[1];
const never = context.options[0] === "never";
const exceptOneLine = Boolean(options && options.omitLastInOneLineBlock);
const beforeStatementContinuationChars = options && options.beforeStatementContinuationChars || "any";
const sourceCode = context.getSourceCode();
//--------------------------------------------------------------------------
// Helpers
//--------------------------------------------------------------------------
/**
* Reports a semicolon error with appropriate location and message.
* @param {ASTNode} node The node with an extra or missing semicolon.
* @param {boolean} missing True if the semicolon is missing.
* @returns {void}
*/
function report(node, missing) {
const lastToken = sourceCode.getLastToken(node);
let messageId,
fix,
loc;
if (!missing) {
messageId = "missingSemi";
loc = {
start: lastToken.loc.end,
end: astUtils.getNextLocation(sourceCode, lastToken.loc.end)
};
fix = function(fixer) {
return fixer.insertTextAfter(lastToken, ";");
};
} else {
messageId = "extraSemi";
loc = lastToken.loc;
fix = function(fixer) {
/*
* Expand the replacement range to include the surrounding
* tokens to avoid conflicting with no-extra-semi.
* https://github.com/eslint/eslint/issues/7928
*/
return new FixTracker(fixer, sourceCode)
.retainSurroundingTokens(lastToken)
.remove(lastToken);
};
}
context.report({
node,
loc,
messageId,
fix
});
}
/**
* Check whether a given semicolon token is redundant.
* @param {Token} semiToken A semicolon token to check.
* @returns {boolean} `true` if the next token is `;` or `}`.
*/
function isRedundantSemi(semiToken) {
const nextToken = sourceCode.getTokenAfter(semiToken);
return (
!nextToken ||
astUtils.isClosingBraceToken(nextToken) ||
astUtils.isSemicolonToken(nextToken)
);
}
/**
* Check whether a given token is the closing brace of an arrow function.
* @param {Token} lastToken A token to check.
* @returns {boolean} `true` if the token is the closing brace of an arrow function.
*/
function isEndOfArrowBlock(lastToken) {
if (!astUtils.isClosingBraceToken(lastToken)) {
return false;
}
const node = sourceCode.getNodeByRangeIndex(lastToken.range[0]);
return (
node.type === "BlockStatement" &&
node.parent.type === "ArrowFunctionExpression"
);
}
/**
* Checks if a given PropertyDefinition node followed by a semicolon
* can safely remove that semicolon. It is not to safe to remove if
* the class field name is "get", "set", or "static", or if
* followed by a generator method.
* @param {ASTNode} node The node to check.
* @returns {boolean} `true` if the node cannot have the semicolon
* removed.
*/
function maybeClassFieldAsiHazard(node) {
if (node.type !== "PropertyDefinition") {
return false;
}
/*
* Computed property names and non-identifiers are always safe
* as they can be distinguished from keywords easily.
*/
const needsNameCheck = !node.computed && node.key.type === "Identifier";
/*
* Certain names are problematic unless they also have a
* a way to distinguish between keywords and property
* names.
*/
if (needsNameCheck && unsafeClassFieldNames.has(node.key.name)) {
/*
* Special case: If the field name is `static`,
* it is only valid if the field is marked as static,
* so "static static" is okay but "static" is not.
*/
const isStaticStatic = node.static && node.key.name === "static";
/*
* For other unsafe names, we only care if there is no
* initializer. No initializer = hazard.
*/
if (!isStaticStatic && !node.value) {
return true;
}
}
const followingToken = sourceCode.getTokenAfter(node);
return unsafeClassFieldFollowers.has(followingToken.value);
}
/**
* Check whether a given node is on the same line with the next token.
* @param {Node} node A statement node to check.
* @returns {boolean} `true` if the node is on the same line with the next token.
*/
function isOnSameLineWithNextToken(node) {
const prevToken = sourceCode.getLastToken(node, 1);
const nextToken = sourceCode.getTokenAfter(node);
return !!nextToken && astUtils.isTokenOnSameLine(prevToken, nextToken);
}
/**
* Check whether a given node can connect the next line if the next line is unreliable.
* @param {Node} node A statement node to check.
* @returns {boolean} `true` if the node can connect the next line.
*/
function maybeAsiHazardAfter(node) {
const t = node.type;
if (t === "DoWhileStatement" ||
t === "BreakStatement" ||
t === "ContinueStatement" ||
t === "DebuggerStatement" ||
t === "ImportDeclaration" ||
t === "ExportAllDeclaration"
) {
return false;
}
if (t === "ReturnStatement") {
return Boolean(node.argument);
}
if (t === "ExportNamedDeclaration") {
return Boolean(node.declaration);
}
if (isEndOfArrowBlock(sourceCode.getLastToken(node, 1))) {
return false;
}
return true;
}
/**
* Check whether a given token can connect the previous statement.
* @param {Token} token A token to check.
* @returns {boolean} `true` if the token is one of `[`, `(`, `/`, `+`, `-`, ```, `++`, and `--`.
*/
function maybeAsiHazardBefore(token) {
return (
Boolean(token) &&
OPT_OUT_PATTERN.test(token.value) &&
token.value !== "++" &&
token.value !== "--"
);
}
/**
* Check if the semicolon of a given node is unnecessary, only true if:
* - next token is a valid statement divider (`;` or `}`).
* - next token is on a new line and the node is not connectable to the new line.
* @param {Node} node A statement node to check.
* @returns {boolean} whether the semicolon is unnecessary.
*/
function canRemoveSemicolon(node) {
if (isRedundantSemi(sourceCode.getLastToken(node))) {
return true; // `;;` or `;}`
}
if (maybeClassFieldAsiHazard(node)) {
return false;
}
if (isOnSameLineWithNextToken(node)) {
return false; // One liner.
}
// continuation characters should not apply to class fields
if (
node.type !== "PropertyDefinition" &&
beforeStatementContinuationChars === "never" &&
!maybeAsiHazardAfter(node)
) {
return true; // ASI works. This statement doesn't connect to the next.
}
if (!maybeAsiHazardBefore(sourceCode.getTokenAfter(node))) {
return true; // ASI works. The next token doesn't connect to this statement.
}
return false;
}
/**
* Checks a node to see if it's the last item in a one-liner block.
* Block is any `BlockStatement` or `StaticBlock` node. Block is a one-liner if its
* braces (and consequently everything between them) are on the same line.
* @param {ASTNode} node The node to check.
* @returns {boolean} whether the node is the last item in a one-liner block.
*/
function isLastInOneLinerBlock(node) {
const parent = node.parent;
const nextToken = sourceCode.getTokenAfter(node);
if (!nextToken || nextToken.value !== "}") {
return false;
}
if (parent.type === "BlockStatement") {
return parent.loc.start.line === parent.loc.end.line;
}
if (parent.type === "StaticBlock") {
const openingBrace = sourceCode.getFirstToken(parent, { skip: 1 }); // skip the `static` token
return openingBrace.loc.start.line === parent.loc.end.line;
}
return false;
}
/**
* Checks a node to see if it's followed by a semicolon.
* @param {ASTNode} node The node to check.
* @returns {void}
*/
function checkForSemicolon(node) {
const isSemi = astUtils.isSemicolonToken(sourceCode.getLastToken(node));
if (never) {
if (isSemi && canRemoveSemicolon(node)) {
report(node, true);
} else if (
!isSemi && beforeStatementContinuationChars === "always" &&
node.type !== "PropertyDefinition" &&
maybeAsiHazardBefore(sourceCode.getTokenAfter(node))
) {
report(node);
}
} else {
const oneLinerBlock = (exceptOneLine && isLastInOneLinerBlock(node));
if (isSemi && oneLinerBlock) {
report(node, true);
} else if (!isSemi && !oneLinerBlock) {
report(node);
}
}
}
/**
* Checks to see if there's a semicolon after a variable declaration.
* @param {ASTNode} node The node to check.
* @returns {void}
*/
function checkForSemicolonForVariableDeclaration(node) {
const parent = node.parent;
if ((parent.type !== "ForStatement" || parent.init !== node) &&
(!/^For(?:In|Of)Statement/u.test(parent.type) || parent.left !== node)
) {
checkForSemicolon(node);
}
}
//--------------------------------------------------------------------------
// Public API
//--------------------------------------------------------------------------
return {
VariableDeclaration: checkForSemicolonForVariableDeclaration,
ExpressionStatement: checkForSemicolon,
ReturnStatement: checkForSemicolon,
ThrowStatement: checkForSemicolon,
DoWhileStatement: checkForSemicolon,
DebuggerStatement: checkForSemicolon,
BreakStatement: checkForSemicolon,
ContinueStatement: checkForSemicolon,
ImportDeclaration: checkForSemicolon,
ExportAllDeclaration: checkForSemicolon,
ExportNamedDeclaration(node) {
if (!node.declaration) {
checkForSemicolon(node);
}
},
ExportDefaultDeclaration(node) {
if (!/(?:Class|Function)Declaration/u.test(node.declaration.type)) {
checkForSemicolon(node);
}
},
PropertyDefinition: checkForSemicolon
};
}
};
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