eslint/tools/internal-rules/no-invalid-meta.js

   1 /**
   2  * @fileoverview Internal rule to prevent missing or invalid meta property in core rules.
   3  * @author Vitor Balocco
   4  */
   5
   6 "use strict";
   7
   8 //------------------------------------------------------------------------------
   9 // Helpers
  10 //------------------------------------------------------------------------------
  11
  12 /**
  13  * Gets the property of the Object node passed in that has the name specified.
  14  * @param {string} property Name of the property to return.
  15  * @param {ASTNode} node The ObjectExpression node.
  16  * @returns {ASTNode} The Property node or null if not found.
  17  */
  18 function getPropertyFromObject(property, node) {
  19     const properties = node.properties;
  20
  21     if (!Array.isArray(properties)) {
  22
  23         return null;
  24     }
  25
  26     for (let i = 0; i < properties.length; i++) {
  27         if (properties[i].key.name === property) {
  28             return properties[i];
  29         }
  30     }
  31
  32     return null;
  33 }
  34
  35 /**
  36  * Extracts the `meta` property from the ObjectExpression that all rules export.
  37  * @param {ASTNode} exportsNode ObjectExpression node that the rule exports.
  38  * @returns {ASTNode} The `meta` Property node or null if not found.
  39  */
  40 function getMetaPropertyFromExportsNode(exportsNode) {
  41     return getPropertyFromObject("meta", exportsNode);
  42 }
  43
  44 /**
  45  * Whether this `meta` ObjectExpression has a `docs` property defined or not.
  46  * @param {ASTNode} metaPropertyNode The `meta` ObjectExpression for this rule.
  47  * @returns {boolean} `true` if a `docs` property exists.
  48  */
  49 function hasMetaDocs(metaPropertyNode) {
  50     return Boolean(getPropertyFromObject("docs", metaPropertyNode.value));
  51 }
  52
  53 /**
  54  * Whether this `meta` ObjectExpression has a `docs.recommended` property defined or not.
  55  * @param {ASTNode} metaPropertyNode The `meta` ObjectExpression for this rule.
  56  * @returns {boolean} `true` if a `docs.recommended` property exists.
  57  */
  58 function hasMetaDocsRecommended(metaPropertyNode) {
  59     const metaDocs = getPropertyFromObject("docs", metaPropertyNode.value);
  60
  61     return metaDocs && getPropertyFromObject("recommended", metaDocs.value);
  62 }
  63
  64 /**
  65  * Checks the validity of the meta definition of this rule and reports any errors found.
  66  * @param {RuleContext} context The ESLint rule context.
  67  * @param {ASTNode} exportsNode ObjectExpression node that the rule exports.
  68  * @returns {void}
  69  */
  70 function checkMetaValidity(context, exportsNode) {
  71     const metaProperty = getMetaPropertyFromExportsNode(exportsNode);
  72
  73     if (!metaProperty) {
  74         context.report({ node: exportsNode, messageId: "missingMeta" });
  75         return;
  76     }
  77
  78     if (!hasMetaDocs(metaProperty)) {
  79         context.report({ node: metaProperty, messageId: "missingMetaDocs" });
  80         return;
  81     }
  82
  83     if (!hasMetaDocsRecommended(metaProperty)) {
  84         context.report({ node: metaProperty, messageId: "missingMetaDocsRecommended" });
  85     }
  86 }
  87
  88 //------------------------------------------------------------------------------
  89 // Rule Definition
  90 //------------------------------------------------------------------------------
  91
  92 module.exports = {
  93     meta: {
  94         docs: {
  95             description: "Enforce correct use of `meta` property in core rules",
  96             recommended: false
  97         },
  98         type: "problem",
  99         schema: [],
 100         messages: {
 101             missingMeta: "Rule is missing a meta property.",
 102             missingMetaDocs: "Rule is missing a meta.docs property.",
 103             missingMetaDocsRecommended: "Rule is missing a meta.docs.recommended property.",
 104             noExport: "Rule does not export anything. Make sure rule exports an object according to new rule format."
 105         }
 106     },
 107
 108     create(context) {
 109         let exportsNode;
 110
 111         return {
 112             AssignmentExpression(node) {
 113                 if (node.left &&
 114                     node.right &&
 115                     node.left.type === "MemberExpression" &&
 116                     node.left.object.name === "module" &&
 117                     node.left.property.name === "exports") {
 118
 119                     exportsNode = node.right;
 120                 }
 121             },
 122
 123             "Program:exit"(node) {
 124                 if (!exportsNode) {
 125                     context.report({
 126                         node,
 127                         messageId: "noExport"
 128                     });
 129                 } else {
 130                     checkMetaValidity(context, exportsNode);
 131                 }
 132             }
 133         };
 134     }
 135 };