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app_vue/node_modules/eslint/lib/rules/prefer-promise-reject-errors.js

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+/**
+ * @fileoverview restrict values that can be used as Promise rejection reasons
+ * @author Teddy Katz
+ */
+"use strict";
+
+const astUtils = require("./utils/ast-utils");
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+module.exports = {
+    meta: {
+        type: "suggestion",
+
+        docs: {
+            description: "require using Error objects as Promise rejection reasons",
+            category: "Best Practices",
+            recommended: false,
+            url: "https://eslint.org/docs/rules/prefer-promise-reject-errors"
+        },
+
+        fixable: null,
+
+        schema: [
+            {
+                type: "object",
+                properties: {
+                    allowEmptyReject: { type: "boolean", default: false }
+                },
+                additionalProperties: false
+            }
+        ],
+
+        messages: {
+            rejectAnError: "Expected the Promise rejection reason to be an Error."
+        }
+    },
+
+    create(context) {
+
+        const ALLOW_EMPTY_REJECT = context.options.length && context.options[0].allowEmptyReject;
+
+        //----------------------------------------------------------------------
+        // Helpers
+        //----------------------------------------------------------------------
+
+        /**
+         * Checks the argument of a reject() or Promise.reject() CallExpression, and reports it if it can't be an Error
+         * @param {ASTNode} callExpression A CallExpression node which is used to reject a Promise
+         * @returns {void}
+         */
+        function checkRejectCall(callExpression) {
+            if (!callExpression.arguments.length && ALLOW_EMPTY_REJECT) {
+                return;
+            }
+            if (
+                !callExpression.arguments.length ||
+                !astUtils.couldBeError(callExpression.arguments[0]) ||
+                callExpression.arguments[0].type === "Identifier" && callExpression.arguments[0].name === "undefined"
+            ) {
+                context.report({
+                    node: callExpression,
+                    messageId: "rejectAnError"
+                });
+            }
+        }
+
+        /**
+         * Determines whether a function call is a Promise.reject() call
+         * @param {ASTNode} node A CallExpression node
+         * @returns {boolean} `true` if the call is a Promise.reject() call
+         */
+        function isPromiseRejectCall(node) {
+            return astUtils.isSpecificMemberAccess(node.callee, "Promise", "reject");
+        }
+
+        //----------------------------------------------------------------------
+        // Public
+        //----------------------------------------------------------------------
+
+        return {
+
+            // Check `Promise.reject(value)` calls.
+            CallExpression(node) {
+                if (isPromiseRejectCall(node)) {
+                    checkRejectCall(node);
+                }
+            },
+
+            /*
+             * Check for `new Promise((resolve, reject) => {})`, and check for reject() calls.
+             * This function is run on "NewExpression:exit" instead of "NewExpression" to ensure that
+             * the nodes in the expression already have the `parent` property.
+             */
+            "NewExpression:exit"(node) {
+                if (
+                    node.callee.type === "Identifier" && node.callee.name === "Promise" &&
+                    node.arguments.length && astUtils.isFunction(node.arguments[0]) &&
+                    node.arguments[0].params.length > 1 && node.arguments[0].params[1].type === "Identifier"
+                ) {
+                    context.getDeclaredVariables(node.arguments[0])
+
+                        /*
+                         * Find the first variable that matches the second parameter's name.
+                         * If the first parameter has the same name as the second parameter, then the variable will actually
+                         * be "declared" when the first parameter is evaluated, but then it will be immediately overwritten
+                         * by the second parameter. It's not possible for an expression with the variable to be evaluated before
+                         * the variable is overwritten, because functions with duplicate parameters cannot have destructuring or
+                         * default assignments in their parameter lists. Therefore, it's not necessary to explicitly account for
+                         * this case.
+                         */
+                        .find(variable => variable.name === node.arguments[0].params[1].name)
+
+                        // Get the references to that variable.
+                        .references
+
+                        // Only check the references that read the parameter's value.
+                        .filter(ref => ref.isRead())
+
+                        // Only check the references that are used as the callee in a function call, e.g. `reject(foo)`.
+                        .filter(ref => ref.identifier.parent.type === "CallExpression" && ref.identifier === ref.identifier.parent.callee)
+
+                        // Check the argument of the function call to determine whether it's an Error.
+                        .forEach(ref => checkRejectCall(ref.identifier.parent));
+                }
+            }
+        };
+    }
+};