mirror of
https://github.com/idanoo/GoScrobble.git
synced 2024-11-23 00:45:16 +00:00
214 lines
7.4 KiB
JavaScript
214 lines
7.4 KiB
JavaScript
/**
|
|
* @fileoverview Rule to flag unnecessary bind calls
|
|
* @author Bence Dányi <bence@danyi.me>
|
|
*/
|
|
"use strict";
|
|
|
|
//------------------------------------------------------------------------------
|
|
// Requirements
|
|
//------------------------------------------------------------------------------
|
|
|
|
const astUtils = require("./utils/ast-utils");
|
|
|
|
//------------------------------------------------------------------------------
|
|
// Helpers
|
|
//------------------------------------------------------------------------------
|
|
|
|
const SIDE_EFFECT_FREE_NODE_TYPES = new Set(["Literal", "Identifier", "ThisExpression", "FunctionExpression"]);
|
|
|
|
//------------------------------------------------------------------------------
|
|
// Rule Definition
|
|
//------------------------------------------------------------------------------
|
|
|
|
module.exports = {
|
|
meta: {
|
|
type: "suggestion",
|
|
|
|
docs: {
|
|
description: "disallow unnecessary calls to `.bind()`",
|
|
category: "Best Practices",
|
|
recommended: false,
|
|
url: "https://eslint.org/docs/rules/no-extra-bind"
|
|
},
|
|
|
|
schema: [],
|
|
fixable: "code",
|
|
|
|
messages: {
|
|
unexpected: "The function binding is unnecessary."
|
|
}
|
|
},
|
|
|
|
create(context) {
|
|
const sourceCode = context.getSourceCode();
|
|
let scopeInfo = null;
|
|
|
|
/**
|
|
* Checks if a node is free of side effects.
|
|
*
|
|
* This check is stricter than it needs to be, in order to keep the implementation simple.
|
|
* @param {ASTNode} node A node to check.
|
|
* @returns {boolean} True if the node is known to be side-effect free, false otherwise.
|
|
*/
|
|
function isSideEffectFree(node) {
|
|
return SIDE_EFFECT_FREE_NODE_TYPES.has(node.type);
|
|
}
|
|
|
|
/**
|
|
* Reports a given function node.
|
|
* @param {ASTNode} node A node to report. This is a FunctionExpression or
|
|
* an ArrowFunctionExpression.
|
|
* @returns {void}
|
|
*/
|
|
function report(node) {
|
|
const memberNode = node.parent;
|
|
const callNode = memberNode.parent.type === "ChainExpression"
|
|
? memberNode.parent.parent
|
|
: memberNode.parent;
|
|
|
|
context.report({
|
|
node: callNode,
|
|
messageId: "unexpected",
|
|
loc: memberNode.property.loc,
|
|
|
|
fix(fixer) {
|
|
if (!isSideEffectFree(callNode.arguments[0])) {
|
|
return null;
|
|
}
|
|
|
|
/*
|
|
* The list of the first/last token pair of a removal range.
|
|
* This is two parts because closing parentheses may exist between the method name and arguments.
|
|
* E.g. `(function(){}.bind ) (obj)`
|
|
* ^^^^^ ^^^^^ < removal ranges
|
|
* E.g. `(function(){}?.['bind'] ) ?.(obj)`
|
|
* ^^^^^^^^^^ ^^^^^^^ < removal ranges
|
|
*/
|
|
const tokenPairs = [
|
|
[
|
|
|
|
// `.`, `?.`, or `[` token.
|
|
sourceCode.getTokenAfter(
|
|
memberNode.object,
|
|
astUtils.isNotClosingParenToken
|
|
),
|
|
|
|
// property name or `]` token.
|
|
sourceCode.getLastToken(memberNode)
|
|
],
|
|
[
|
|
|
|
// `?.` or `(` token of arguments.
|
|
sourceCode.getTokenAfter(
|
|
memberNode,
|
|
astUtils.isNotClosingParenToken
|
|
),
|
|
|
|
// `)` token of arguments.
|
|
sourceCode.getLastToken(callNode)
|
|
]
|
|
];
|
|
const firstTokenToRemove = tokenPairs[0][0];
|
|
const lastTokenToRemove = tokenPairs[1][1];
|
|
|
|
if (sourceCode.commentsExistBetween(firstTokenToRemove, lastTokenToRemove)) {
|
|
return null;
|
|
}
|
|
|
|
return tokenPairs.map(([start, end]) =>
|
|
fixer.removeRange([start.range[0], end.range[1]]));
|
|
}
|
|
});
|
|
}
|
|
|
|
/**
|
|
* Checks whether or not a given function node is the callee of `.bind()`
|
|
* method.
|
|
*
|
|
* e.g. `(function() {}.bind(foo))`
|
|
* @param {ASTNode} node A node to report. This is a FunctionExpression or
|
|
* an ArrowFunctionExpression.
|
|
* @returns {boolean} `true` if the node is the callee of `.bind()` method.
|
|
*/
|
|
function isCalleeOfBindMethod(node) {
|
|
if (!astUtils.isSpecificMemberAccess(node.parent, null, "bind")) {
|
|
return false;
|
|
}
|
|
|
|
// The node of `*.bind` member access.
|
|
const bindNode = node.parent.parent.type === "ChainExpression"
|
|
? node.parent.parent
|
|
: node.parent;
|
|
|
|
return (
|
|
bindNode.parent.type === "CallExpression" &&
|
|
bindNode.parent.callee === bindNode &&
|
|
bindNode.parent.arguments.length === 1 &&
|
|
bindNode.parent.arguments[0].type !== "SpreadElement"
|
|
);
|
|
}
|
|
|
|
/**
|
|
* Adds a scope information object to the stack.
|
|
* @param {ASTNode} node A node to add. This node is a FunctionExpression
|
|
* or a FunctionDeclaration node.
|
|
* @returns {void}
|
|
*/
|
|
function enterFunction(node) {
|
|
scopeInfo = {
|
|
isBound: isCalleeOfBindMethod(node),
|
|
thisFound: false,
|
|
upper: scopeInfo
|
|
};
|
|
}
|
|
|
|
/**
|
|
* Removes the scope information object from the top of the stack.
|
|
* At the same time, this reports the function node if the function has
|
|
* `.bind()` and the `this` keywords found.
|
|
* @param {ASTNode} node A node to remove. This node is a
|
|
* FunctionExpression or a FunctionDeclaration node.
|
|
* @returns {void}
|
|
*/
|
|
function exitFunction(node) {
|
|
if (scopeInfo.isBound && !scopeInfo.thisFound) {
|
|
report(node);
|
|
}
|
|
|
|
scopeInfo = scopeInfo.upper;
|
|
}
|
|
|
|
/**
|
|
* Reports a given arrow function if the function is callee of `.bind()`
|
|
* method.
|
|
* @param {ASTNode} node A node to report. This node is an
|
|
* ArrowFunctionExpression.
|
|
* @returns {void}
|
|
*/
|
|
function exitArrowFunction(node) {
|
|
if (isCalleeOfBindMethod(node)) {
|
|
report(node);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Set the mark as the `this` keyword was found in this scope.
|
|
* @returns {void}
|
|
*/
|
|
function markAsThisFound() {
|
|
if (scopeInfo) {
|
|
scopeInfo.thisFound = true;
|
|
}
|
|
}
|
|
|
|
return {
|
|
"ArrowFunctionExpression:exit": exitArrowFunction,
|
|
FunctionDeclaration: enterFunction,
|
|
"FunctionDeclaration:exit": exitFunction,
|
|
FunctionExpression: enterFunction,
|
|
"FunctionExpression:exit": exitFunction,
|
|
ThisExpression: markAsThisFound
|
|
};
|
|
}
|
|
};
|