/** * @fileoverview Rule to flag when IIFE is not wrapped in parens * @author Ilya Volodin */ "use strict"; //------------------------------------------------------------------------------ // Requirements //------------------------------------------------------------------------------ const astUtils = require("./utils/ast-utils"); const eslintUtils = require("eslint-utils"); //---------------------------------------------------------------------- // Helpers //---------------------------------------------------------------------- /** * Check if the given node is callee of a `NewExpression` node * @param {ASTNode} node node to check * @returns {boolean} True if the node is callee of a `NewExpression` node * @private */ function isCalleeOfNewExpression(node) { const maybeCallee = node.parent.type === "ChainExpression" ? node.parent : node; return ( maybeCallee.parent.type === "NewExpression" && maybeCallee.parent.callee === maybeCallee ); } //------------------------------------------------------------------------------ // Rule Definition //------------------------------------------------------------------------------ module.exports = { meta: { type: "layout", docs: { description: "require parentheses around immediate `function` invocations", category: "Best Practices", recommended: false, url: "https://eslint.org/docs/rules/wrap-iife" }, schema: [ { enum: ["outside", "inside", "any"] }, { type: "object", properties: { functionPrototypeMethods: { type: "boolean", default: false } }, additionalProperties: false } ], fixable: "code", messages: { wrapInvocation: "Wrap an immediate function invocation in parentheses.", wrapExpression: "Wrap only the function expression in parens.", moveInvocation: "Move the invocation into the parens that contain the function." } }, create(context) { const style = context.options[0] || "outside"; const includeFunctionPrototypeMethods = context.options[1] && context.options[1].functionPrototypeMethods; const sourceCode = context.getSourceCode(); /** * Check if the node is wrapped in any (). All parens count: grouping parens and parens for constructs such as if() * @param {ASTNode} node node to evaluate * @returns {boolean} True if it is wrapped in any parens * @private */ function isWrappedInAnyParens(node) { return astUtils.isParenthesised(sourceCode, node); } /** * Check if the node is wrapped in grouping (). Parens for constructs such as if() don't count * @param {ASTNode} node node to evaluate * @returns {boolean} True if it is wrapped in grouping parens * @private */ function isWrappedInGroupingParens(node) { return eslintUtils.isParenthesized(1, node, sourceCode); } /** * Get the function node from an IIFE * @param {ASTNode} node node to evaluate * @returns {ASTNode} node that is the function expression of the given IIFE, or null if none exist */ function getFunctionNodeFromIIFE(node) { const callee = astUtils.skipChainExpression(node.callee); if (callee.type === "FunctionExpression") { return callee; } if (includeFunctionPrototypeMethods && callee.type === "MemberExpression" && callee.object.type === "FunctionExpression" && (astUtils.getStaticPropertyName(callee) === "call" || astUtils.getStaticPropertyName(callee) === "apply") ) { return callee.object; } return null; } return { CallExpression(node) { const innerNode = getFunctionNodeFromIIFE(node); if (!innerNode) { return; } const isCallExpressionWrapped = isWrappedInAnyParens(node), isFunctionExpressionWrapped = isWrappedInAnyParens(innerNode); if (!isCallExpressionWrapped && !isFunctionExpressionWrapped) { context.report({ node, messageId: "wrapInvocation", fix(fixer) { const nodeToSurround = style === "inside" ? innerNode : node; return fixer.replaceText(nodeToSurround, `(${sourceCode.getText(nodeToSurround)})`); } }); } else if (style === "inside" && !isFunctionExpressionWrapped) { context.report({ node, messageId: "wrapExpression", fix(fixer) { // The outer call expression will always be wrapped at this point. if (isWrappedInGroupingParens(node) && !isCalleeOfNewExpression(node)) { /* * Parenthesize the function expression and remove unnecessary grouping parens around the call expression. * Replace the range between the end of the function expression and the end of the call expression. * for example, in `(function(foo) {}(bar))`, the range `(bar))` should get replaced with `)(bar)`. */ const parenAfter = sourceCode.getTokenAfter(node); return fixer.replaceTextRange( [innerNode.range[1], parenAfter.range[1]], `)${sourceCode.getText().slice(innerNode.range[1], parenAfter.range[0])}` ); } /* * Call expression is wrapped in mandatory parens such as if(), or in necessary grouping parens. * These parens cannot be removed, so just parenthesize the function expression. */ return fixer.replaceText(innerNode, `(${sourceCode.getText(innerNode)})`); } }); } else if (style === "outside" && !isCallExpressionWrapped) { context.report({ node, messageId: "moveInvocation", fix(fixer) { /* * The inner function expression will always be wrapped at this point. * It's only necessary to replace the range between the end of the function expression * and the call expression. For example, in `(function(foo) {})(bar)`, the range `)(bar)` * should get replaced with `(bar))`. */ const parenAfter = sourceCode.getTokenAfter(innerNode); return fixer.replaceTextRange( [parenAfter.range[0], node.range[1]], `${sourceCode.getText().slice(parenAfter.range[1], node.range[1])})` ); } }); } } }; } };