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/**
* @fileoverview Rule to flag bitwise identifiers
* @author Nicholas C. Zakas
*/
"use strict";
/*
*
* Set of bitwise operators.
*
*/
const BITWISE_OPERATORS = [
"^", "|", "&", "<<", ">>", ">>>",
"^=", "|=", "&=", "<<=", ">>=", ">>>=",
"~"
];
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
/** @type {import('../shared/types').Rule} */
module.exports = {
meta: {
type: "suggestion",
docs: {
description: "Disallow bitwise operators",
recommended: false,
url: "https://eslint.org/docs/latest/rules/no-bitwise"
},
schema: [
{
type: "object",
properties: {
allow: {
type: "array",
items: {
enum: BITWISE_OPERATORS
},
uniqueItems: true
},
int32Hint: {
type: "boolean",
default: false
}
},
additionalProperties: false
}
],
messages: {
unexpected: "Unexpected use of '{{operator}}'."
}
},
create(context) {
const options = context.options[0] || {};
const allowed = options.allow || [];
const int32Hint = options.int32Hint === true;
/**
* Reports an unexpected use of a bitwise operator.
* @param {ASTNode} node Node which contains the bitwise operator.
* @returns {void}
*/
function report(node) {
context.report({ node, messageId: "unexpected", data: { operator: node.operator } });
}
/**
* Checks if the given node has a bitwise operator.
* @param {ASTNode} node The node to check.
* @returns {boolean} Whether or not the node has a bitwise operator.
*/
function hasBitwiseOperator(node) {
return BITWISE_OPERATORS.includes(node.operator);
}
/**
* Checks if exceptions were provided, e.g. `{ allow: ['~', '|'] }`.
* @param {ASTNode} node The node to check.
* @returns {boolean} Whether or not the node has a bitwise operator.
*/
function allowedOperator(node) {
return allowed.includes(node.operator);
}
/**
* Checks if the given bitwise operator is used for integer typecasting, i.e. "|0"
* @param {ASTNode} node The node to check.
* @returns {boolean} whether the node is used in integer typecasting.
*/
function isInt32Hint(node) {
return int32Hint && node.operator === "|" && node.right &&
node.right.type === "Literal" && node.right.value === 0;
}
/**
* Report if the given node contains a bitwise operator.
* @param {ASTNode} node The node to check.
* @returns {void}
*/
function checkNodeForBitwiseOperator(node) {
if (hasBitwiseOperator(node) && !allowedOperator(node) && !isInt32Hint(node)) {
report(node);
}
}
return {
AssignmentExpression: checkNodeForBitwiseOperator,
BinaryExpression: checkNodeForBitwiseOperator,
UnaryExpression: checkNodeForBitwiseOperator
};
}
};