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