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/**
* @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
//------------------------------------------------------------------------------
/** @type {import('../shared/types').Rule} */
module.exports = {
meta: {
type: "layout",
docs: {
description: "Require parentheses around immediate `function` invocations",
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])})`
);
}
});
}
}
};
}
};