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							- /**
 
-  * @fileoverview Flag expressions in statement position that do not side effect
 
-  * @author Michael Ficarra
 
-  */
 
- "use strict";
 
- //------------------------------------------------------------------------------
 
- // Rule Definition
 
- //------------------------------------------------------------------------------
 
- /**
 
-  * Returns `true`.
 
-  * @returns {boolean} `true`.
 
-  */
 
- function alwaysTrue() {
 
-     return true;
 
- }
 
- /**
 
-  * Returns `false`.
 
-  * @returns {boolean} `false`.
 
-  */
 
- function alwaysFalse() {
 
-     return false;
 
- }
 
- module.exports = {
 
-     meta: {
 
-         type: "suggestion",
 
-         docs: {
 
-             description: "disallow unused expressions",
 
-             category: "Best Practices",
 
-             recommended: false,
 
-             url: "https://eslint.org/docs/rules/no-unused-expressions"
 
-         },
 
-         schema: [
 
-             {
 
-                 type: "object",
 
-                 properties: {
 
-                     allowShortCircuit: {
 
-                         type: "boolean",
 
-                         default: false
 
-                     },
 
-                     allowTernary: {
 
-                         type: "boolean",
 
-                         default: false
 
-                     },
 
-                     allowTaggedTemplates: {
 
-                         type: "boolean",
 
-                         default: false
 
-                     }
 
-                 },
 
-                 additionalProperties: false
 
-             }
 
-         ],
 
-         messages: {
 
-             unusedExpression: "Expected an assignment or function call and instead saw an expression."
 
-         }
 
-     },
 
-     create(context) {
 
-         const config = context.options[0] || {},
 
-             allowShortCircuit = config.allowShortCircuit || false,
 
-             allowTernary = config.allowTernary || false,
 
-             allowTaggedTemplates = config.allowTaggedTemplates || false;
 
-         // eslint-disable-next-line jsdoc/require-description
 
-         /**
 
-          * @param {ASTNode} node any node
 
-          * @returns {boolean} whether the given node structurally represents a directive
 
-          */
 
-         function looksLikeDirective(node) {
 
-             return node.type === "ExpressionStatement" &&
 
-                 node.expression.type === "Literal" && typeof node.expression.value === "string";
 
-         }
 
-         // eslint-disable-next-line jsdoc/require-description
 
-         /**
 
-          * @param {Function} predicate ([a] -> Boolean) the function used to make the determination
 
-          * @param {a[]} list the input list
 
-          * @returns {a[]} the leading sequence of members in the given list that pass the given predicate
 
-          */
 
-         function takeWhile(predicate, list) {
 
-             for (let i = 0; i < list.length; ++i) {
 
-                 if (!predicate(list[i])) {
 
-                     return list.slice(0, i);
 
-                 }
 
-             }
 
-             return list.slice();
 
-         }
 
-         // eslint-disable-next-line jsdoc/require-description
 
-         /**
 
-          * @param {ASTNode} node a Program or BlockStatement node
 
-          * @returns {ASTNode[]} the leading sequence of directive nodes in the given node's body
 
-          */
 
-         function directives(node) {
 
-             return takeWhile(looksLikeDirective, node.body);
 
-         }
 
-         // eslint-disable-next-line jsdoc/require-description
 
-         /**
 
-          * @param {ASTNode} node any node
 
-          * @param {ASTNode[]} ancestors the given node's ancestors
 
-          * @returns {boolean} whether the given node is considered a directive in its current position
 
-          */
 
-         function isDirective(node, ancestors) {
 
-             const parent = ancestors[ancestors.length - 1],
 
-                 grandparent = ancestors[ancestors.length - 2];
 
-             return (parent.type === "Program" || parent.type === "BlockStatement" &&
 
-                     (/Function/u.test(grandparent.type))) &&
 
-                     directives(parent).indexOf(node) >= 0;
 
-         }
 
-         /**
 
-          * The member functions return `true` if the type has no side-effects.
 
-          * Unknown nodes are handled as `false`, then this rule ignores those.
 
-          */
 
-         const Checker = Object.assign(Object.create(null), {
 
-             isDisallowed(node) {
 
-                 return (Checker[node.type] || alwaysFalse)(node);
 
-             },
 
-             ArrayExpression: alwaysTrue,
 
-             ArrowFunctionExpression: alwaysTrue,
 
-             BinaryExpression: alwaysTrue,
 
-             ChainExpression(node) {
 
-                 return Checker.isDisallowed(node.expression);
 
-             },
 
-             ClassExpression: alwaysTrue,
 
-             ConditionalExpression(node) {
 
-                 if (allowTernary) {
 
-                     return Checker.isDisallowed(node.consequent) || Checker.isDisallowed(node.alternate);
 
-                 }
 
-                 return true;
 
-             },
 
-             FunctionExpression: alwaysTrue,
 
-             Identifier: alwaysTrue,
 
-             Literal: alwaysTrue,
 
-             LogicalExpression(node) {
 
-                 if (allowShortCircuit) {
 
-                     return Checker.isDisallowed(node.right);
 
-                 }
 
-                 return true;
 
-             },
 
-             MemberExpression: alwaysTrue,
 
-             MetaProperty: alwaysTrue,
 
-             ObjectExpression: alwaysTrue,
 
-             SequenceExpression: alwaysTrue,
 
-             TaggedTemplateExpression() {
 
-                 return !allowTaggedTemplates;
 
-             },
 
-             TemplateLiteral: alwaysTrue,
 
-             ThisExpression: alwaysTrue,
 
-             UnaryExpression(node) {
 
-                 return node.operator !== "void" && node.operator !== "delete";
 
-             }
 
-         });
 
-         return {
 
-             ExpressionStatement(node) {
 
-                 if (Checker.isDisallowed(node.expression) && !isDirective(node, context.getAncestors())) {
 
-                     context.report({ node, messageId: "unusedExpression" });
 
-                 }
 
-             }
 
-         };
 
-     }
 
- };
 
 
  |