/** * @fileoverview A rule to choose between single and double quote marks * @author Matt DuVall , Brandon Payton */ "use strict"; //------------------------------------------------------------------------------ // Requirements //------------------------------------------------------------------------------ const astUtils = require("./utils/ast-utils"); //------------------------------------------------------------------------------ // Constants //------------------------------------------------------------------------------ const QUOTE_SETTINGS = { double: { quote: "\"", alternateQuote: "'", description: "doublequote" }, single: { quote: "'", alternateQuote: "\"", description: "singlequote" }, backtick: { quote: "`", alternateQuote: "\"", description: "backtick" } }; // An unescaped newline is a newline preceded by an even number of backslashes. const UNESCAPED_LINEBREAK_PATTERN = new RegExp(String.raw`(^|[^\\])(\\\\)*[${Array.from(astUtils.LINEBREAKS).join("")}]`, "u"); /** * Switches quoting of javascript string between ' " and ` * escaping and unescaping as necessary. * Only escaping of the minimal set of characters is changed. * Note: escaping of newlines when switching from backtick to other quotes is not handled. * @param {string} str A string to convert. * @returns {string} The string with changed quotes. * @private */ QUOTE_SETTINGS.double.convert = QUOTE_SETTINGS.single.convert = QUOTE_SETTINGS.backtick.convert = function(str) { const newQuote = this.quote; const oldQuote = str[0]; if (newQuote === oldQuote) { return str; } return newQuote + str.slice(1, -1).replace(/\\(\$\{|\r\n?|\n|.)|["'`]|\$\{|(\r\n?|\n)/gu, (match, escaped, newline) => { if (escaped === oldQuote || oldQuote === "`" && escaped === "${") { return escaped; // unescape } if (match === newQuote || newQuote === "`" && match === "${") { return `\\${match}`; // escape } if (newline && oldQuote === "`") { return "\\n"; // escape newlines } return match; }) + newQuote; }; const AVOID_ESCAPE = "avoid-escape"; //------------------------------------------------------------------------------ // Rule Definition //------------------------------------------------------------------------------ module.exports = { meta: { type: "layout", docs: { description: "enforce the consistent use of either backticks, double, or single quotes", category: "Stylistic Issues", recommended: false, url: "https://eslint.org/docs/rules/quotes" }, fixable: "code", schema: [ { enum: ["single", "double", "backtick"] }, { anyOf: [ { enum: ["avoid-escape"] }, { type: "object", properties: { avoidEscape: { type: "boolean" }, allowTemplateLiterals: { type: "boolean" } }, additionalProperties: false } ] } ], messages: { wrongQuotes: "Strings must use {{description}}." } }, create(context) { const quoteOption = context.options[0], settings = QUOTE_SETTINGS[quoteOption || "double"], options = context.options[1], allowTemplateLiterals = options && options.allowTemplateLiterals === true, sourceCode = context.getSourceCode(); let avoidEscape = options && options.avoidEscape === true; // deprecated if (options === AVOID_ESCAPE) { avoidEscape = true; } /** * Determines if a given node is part of JSX syntax. * * This function returns `true` in the following cases: * * - `
` ... If the literal is an attribute value, the parent of the literal is `JSXAttribute`. * - `
foo
` ... If the literal is a text content, the parent of the literal is `JSXElement`. * - `<>foo` ... If the literal is a text content, the parent of the literal is `JSXFragment`. * * In particular, this function returns `false` in the following cases: * * - `
` * - `
{"foo"}
` * * In both cases, inside of the braces is handled as normal JavaScript. * The braces are `JSXExpressionContainer` nodes. * @param {ASTNode} node The Literal node to check. * @returns {boolean} True if the node is a part of JSX, false if not. * @private */ function isJSXLiteral(node) { return node.parent.type === "JSXAttribute" || node.parent.type === "JSXElement" || node.parent.type === "JSXFragment"; } /** * Checks whether or not a given node is a directive. * The directive is a `ExpressionStatement` which has only a string literal. * @param {ASTNode} node A node to check. * @returns {boolean} Whether or not the node is a directive. * @private */ function isDirective(node) { return ( node.type === "ExpressionStatement" && node.expression.type === "Literal" && typeof node.expression.value === "string" ); } /** * Checks whether or not a given node is a part of directive prologues. * See also: http://www.ecma-international.org/ecma-262/6.0/#sec-directive-prologues-and-the-use-strict-directive * @param {ASTNode} node A node to check. * @returns {boolean} Whether or not the node is a part of directive prologues. * @private */ function isPartOfDirectivePrologue(node) { const block = node.parent.parent; if (block.type !== "Program" && (block.type !== "BlockStatement" || !astUtils.isFunction(block.parent))) { return false; } // Check the node is at a prologue. for (let i = 0; i < block.body.length; ++i) { const statement = block.body[i]; if (statement === node.parent) { return true; } if (!isDirective(statement)) { break; } } return false; } /** * Checks whether or not a given node is allowed as non backtick. * @param {ASTNode} node A node to check. * @returns {boolean} Whether or not the node is allowed as non backtick. * @private */ function isAllowedAsNonBacktick(node) { const parent = node.parent; switch (parent.type) { // Directive Prologues. case "ExpressionStatement": return isPartOfDirectivePrologue(node); // LiteralPropertyName. case "Property": case "MethodDefinition": return parent.key === node && !parent.computed; // ModuleSpecifier. case "ImportDeclaration": case "ExportNamedDeclaration": case "ExportAllDeclaration": return parent.source === node; // Others don't allow. default: return false; } } /** * Checks whether or not a given TemplateLiteral node is actually using any of the special features provided by template literal strings. * @param {ASTNode} node A TemplateLiteral node to check. * @returns {boolean} Whether or not the TemplateLiteral node is using any of the special features provided by template literal strings. * @private */ function isUsingFeatureOfTemplateLiteral(node) { const hasTag = node.parent.type === "TaggedTemplateExpression" && node === node.parent.quasi; if (hasTag) { return true; } const hasStringInterpolation = node.expressions.length > 0; if (hasStringInterpolation) { return true; } const isMultilineString = node.quasis.length >= 1 && UNESCAPED_LINEBREAK_PATTERN.test(node.quasis[0].value.raw); if (isMultilineString) { return true; } return false; } return { Literal(node) { const val = node.value, rawVal = node.raw; if (settings && typeof val === "string") { let isValid = (quoteOption === "backtick" && isAllowedAsNonBacktick(node)) || isJSXLiteral(node) || astUtils.isSurroundedBy(rawVal, settings.quote); if (!isValid && avoidEscape) { isValid = astUtils.isSurroundedBy(rawVal, settings.alternateQuote) && rawVal.indexOf(settings.quote) >= 0; } if (!isValid) { context.report({ node, messageId: "wrongQuotes", data: { description: settings.description }, fix(fixer) { if (quoteOption === "backtick" && astUtils.hasOctalOrNonOctalDecimalEscapeSequence(rawVal)) { /* * An octal or non-octal decimal escape sequence in a template literal would * produce syntax error, even in non-strict mode. */ return null; } return fixer.replaceText(node, settings.convert(node.raw)); } }); } } }, TemplateLiteral(node) { // Don't throw an error if backticks are expected or a template literal feature is in use. if ( allowTemplateLiterals || quoteOption === "backtick" || isUsingFeatureOfTemplateLiteral(node) ) { return; } context.report({ node, messageId: "wrongQuotes", data: { description: settings.description }, fix(fixer) { if (isPartOfDirectivePrologue(node)) { /* * TemplateLiterals in a directive prologue aren't actually directives, but if they're * in the directive prologue, then fixing them might turn them into directives and change * the behavior of the code. */ return null; } return fixer.replaceText(node, settings.convert(sourceCode.getText(node))); } }); } }; } };