/** * @fileoverview Rule to spot scenarios where a newline looks like it is ending a statement, but is not. * @author Glen Mailer */ 'use strict'; //------------------------------------------------------------------------------ // Requirements //------------------------------------------------------------------------------ const astUtils = require('./utils/ast-utils'); //------------------------------------------------------------------------------ // Rule Definition //------------------------------------------------------------------------------ /** @type {import('../types').Rule.RuleModule} */ module.exports = { meta: { type: 'problem', docs: { description: 'Disallow confusing multiline expressions', recommended: true, url: 'https://eslint.org/docs/latest/rules/no-unexpected-multiline', }, schema: [], messages: { function: 'Unexpected newline between function and ( of function call.', property: 'Unexpected newline between object and [ of property access.', taggedTemplate: 'Unexpected newline between template tag and template literal.', division: 'Unexpected newline between numerator and division operator.', }, }, create(context) { const REGEX_FLAG_MATCHER = /^[gimsuy]+$/u; const sourceCode = context.sourceCode; /** * Check to see if there is a newline between the node and the following open bracket * line's expression * @param {ASTNode} node The node to check. * @param {string} messageId The error messageId to use. * @returns {void} * @private */ function checkForBreakAfter(node, messageId) { const openParen = sourceCode.getTokenAfter( node, astUtils.isNotClosingParenToken ); const nodeExpressionEnd = sourceCode.getTokenBefore(openParen); if (openParen.loc.start.line !== nodeExpressionEnd.loc.end.line) { context.report({ node, loc: openParen.loc, messageId, }); } } //-------------------------------------------------------------------------- // Public API //-------------------------------------------------------------------------- return { MemberExpression(node) { if (!node.computed || node.optional) { return; } checkForBreakAfter(node.object, 'property'); }, TaggedTemplateExpression(node) { const { quasi } = node; // handles common tags, parenthesized tags, and typescript's generic type arguments const tokenBefore = sourceCode.getTokenBefore(quasi); if (tokenBefore.loc.end.line !== quasi.loc.start.line) { context.report({ node, loc: { start: quasi.loc.start, end: { line: quasi.loc.start.line, column: quasi.loc.start.column + 1, }, }, messageId: 'taggedTemplate', }); } }, CallExpression(node) { if (node.arguments.length === 0 || node.optional) { return; } checkForBreakAfter(node.callee, 'function'); }, "BinaryExpression[operator='/'] > BinaryExpression[operator='/'].left"( node ) { const secondSlash = sourceCode.getTokenAfter( node, (token) => token.value === '/' ); const tokenAfterOperator = sourceCode.getTokenAfter(secondSlash); if ( tokenAfterOperator.type === 'Identifier' && REGEX_FLAG_MATCHER.test(tokenAfterOperator.value) && secondSlash.range[1] === tokenAfterOperator.range[0] ) { checkForBreakAfter(node.left, 'division'); } }, }; }, };