diff options
Diffstat (limited to 'tools/node_modules/eslint/lib/rules/no-constant-condition.js')
| -rw-r--r-- | tools/node_modules/eslint/lib/rules/no-constant-condition.js | 201 |
1 files changed, 4 insertions, 197 deletions
diff --git a/tools/node_modules/eslint/lib/rules/no-constant-condition.js b/tools/node_modules/eslint/lib/rules/no-constant-condition.js index 3d08c689aef..a0871fe972d 100644 --- a/tools/node_modules/eslint/lib/rules/no-constant-condition.js +++ b/tools/node_modules/eslint/lib/rules/no-constant-condition.js @@ -5,6 +5,8 @@ "use strict"; +const { isConstant } = require("./utils/ast-utils"); + //------------------------------------------------------------------------------ // Helpers //------------------------------------------------------------------------------ @@ -54,208 +56,13 @@ module.exports = { //-------------------------------------------------------------------------- /** - * Returns literal's value converted to the Boolean type - * @param {ASTNode} node any `Literal` node - * @returns {boolean | null} `true` when node is truthy, `false` when node is falsy, - * `null` when it cannot be determined. - */ - function getBooleanValue(node) { - if (node.value === null) { - - /* - * it might be a null literal or bigint/regex literal in unsupported environments . - * https://github.com/estree/estree/blob/14df8a024956ea289bd55b9c2226a1d5b8a473ee/es5.md#regexpliteral - * https://github.com/estree/estree/blob/14df8a024956ea289bd55b9c2226a1d5b8a473ee/es2020.md#bigintliteral - */ - - if (node.raw === "null") { - return false; - } - - // regex is always truthy - if (typeof node.regex === "object") { - return true; - } - - return null; - } - - return !!node.value; - } - - /** - * Checks if a branch node of LogicalExpression short circuits the whole condition - * @param {ASTNode} node The branch of main condition which needs to be checked - * @param {string} operator The operator of the main LogicalExpression. - * @returns {boolean} true when condition short circuits whole condition - */ - function isLogicalIdentity(node, operator) { - switch (node.type) { - case "Literal": - return (operator === "||" && getBooleanValue(node) === true) || - (operator === "&&" && getBooleanValue(node) === false); - - case "UnaryExpression": - return (operator === "&&" && node.operator === "void"); - - case "LogicalExpression": - - /* - * handles `a && false || b` - * `false` is an identity element of `&&` but not `||` - */ - return operator === node.operator && - ( - isLogicalIdentity(node.left, operator) || - isLogicalIdentity(node.right, operator) - ); - - case "AssignmentExpression": - return ["||=", "&&="].includes(node.operator) && - operator === node.operator.slice(0, -1) && - isLogicalIdentity(node.right, operator); - - // no default - } - return false; - } - - /** - * Checks if an identifier is a reference to a global variable. - * @param {ASTNode} node An identifier node to check. - * @returns {boolean} `true` if the identifier is a reference to a global variable. - */ - function isReferenceToGlobalVariable(node) { - const scope = context.getScope(); - const reference = scope.references.find(ref => ref.identifier === node); - - return Boolean( - reference && - reference.resolved && - reference.resolved.scope.type === "global" && - reference.resolved.defs.length === 0 - ); - } - - /** - * Checks if a node has a constant truthiness value. - * @param {ASTNode} node The AST node to check. - * @param {boolean} inBooleanPosition `true` if checking the test of a - * condition. `false` in all other cases. When `false`, checks if -- for - * both string and number -- if coerced to that type, the value will - * be constant. - * @returns {Bool} true when node's truthiness is constant - * @private - */ - function isConstant(node, inBooleanPosition) { - - // node.elements can return null values in the case of sparse arrays ex. [,] - if (!node) { - return true; - } - switch (node.type) { - case "Literal": - case "ArrowFunctionExpression": - case "FunctionExpression": - return true; - case "ClassExpression": - case "ObjectExpression": - - /** - * In theory objects like: - * - * `{toString: () => a}` - * `{valueOf: () => a}` - * - * Or a classes like: - * - * `class { static toString() { return a } }` - * `class { static valueOf() { return a } }` - * - * Are not constant verifiably when `inBooleanPosition` is - * false, but it's an edge case we've opted not to handle. - */ - return true; - case "TemplateLiteral": - return (inBooleanPosition && node.quasis.some(quasi => quasi.value.cooked.length)) || - node.expressions.every(exp => isConstant(exp, false)); - - case "ArrayExpression": { - if (!inBooleanPosition) { - return node.elements.every(element => isConstant(element, false)); - } - return true; - } - - case "UnaryExpression": - if ( - node.operator === "void" || - node.operator === "typeof" && inBooleanPosition - ) { - return true; - } - - if (node.operator === "!") { - return isConstant(node.argument, true); - } - - return isConstant(node.argument, false); - - case "BinaryExpression": - return isConstant(node.left, false) && - isConstant(node.right, false) && - node.operator !== "in"; - - case "LogicalExpression": { - const isLeftConstant = isConstant(node.left, inBooleanPosition); - const isRightConstant = isConstant(node.right, inBooleanPosition); - const isLeftShortCircuit = (isLeftConstant && isLogicalIdentity(node.left, node.operator)); - const isRightShortCircuit = (inBooleanPosition && isRightConstant && isLogicalIdentity(node.right, node.operator)); - - return (isLeftConstant && isRightConstant) || - isLeftShortCircuit || - isRightShortCircuit; - } - case "NewExpression": - return inBooleanPosition; - case "AssignmentExpression": - if (node.operator === "=") { - return isConstant(node.right, inBooleanPosition); - } - - if (["||=", "&&="].includes(node.operator) && inBooleanPosition) { - return isLogicalIdentity(node.right, node.operator.slice(0, -1)); - } - - return false; - - case "SequenceExpression": - return isConstant(node.expressions[node.expressions.length - 1], inBooleanPosition); - case "SpreadElement": - return isConstant(node.argument, inBooleanPosition); - case "CallExpression": - if (node.callee.type === "Identifier" && node.callee.name === "Boolean") { - if (node.arguments.length === 0 || isConstant(node.arguments[0], true)) { - return isReferenceToGlobalVariable(node.callee); - } - } - return false; - case "Identifier": - return node.name === "undefined" && isReferenceToGlobalVariable(node); - - // no default - } - return false; - } - - /** * Tracks when the given node contains a constant condition. * @param {ASTNode} node The AST node to check. * @returns {void} * @private */ function trackConstantConditionLoop(node) { - if (node.test && isConstant(node.test, true)) { + if (node.test && isConstant(context.getScope(), node.test, true)) { loopsInCurrentScope.add(node); } } @@ -280,7 +87,7 @@ module.exports = { * @private */ function reportIfConstant(node) { - if (node.test && isConstant(node.test, true)) { + if (node.test && isConstant(context.getScope(), node.test, true)) { context.report({ node: node.test, messageId: "unexpected" }); } } |