1 | /**
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2 | * @fileoverview Ensure handling of errors when we know they exist.
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3 | * @author Jamund Ferguson
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4 | */
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5 |
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6 | ;
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7 |
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8 | //------------------------------------------------------------------------------
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9 | // Rule Definition
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10 | //------------------------------------------------------------------------------
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11 |
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12 | module.exports = {
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13 | meta: {
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14 | docs: {
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15 | description: "require error handling in callbacks",
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16 | category: "Node.js and CommonJS",
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17 | recommended: false,
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18 | url: "https://eslint.org/docs/rules/handle-callback-err"
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19 | },
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20 |
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21 | schema: [
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22 | {
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23 | type: "string"
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24 | }
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25 | ]
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26 | },
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27 |
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28 | create(context) {
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29 |
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30 | const errorArgument = context.options[0] || "err";
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31 |
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32 | /**
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33 | * Checks if the given argument should be interpreted as a regexp pattern.
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34 | * @param {string} stringToCheck The string which should be checked.
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35 | * @returns {boolean} Whether or not the string should be interpreted as a pattern.
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36 | */
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37 | function isPattern(stringToCheck) {
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38 | const firstChar = stringToCheck[0];
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39 |
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40 | return firstChar === "^";
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41 | }
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42 |
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43 | /**
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44 | * Checks if the given name matches the configured error argument.
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45 | * @param {string} name The name which should be compared.
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46 | * @returns {boolean} Whether or not the given name matches the configured error variable name.
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47 | */
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48 | function matchesConfiguredErrorName(name) {
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49 | if (isPattern(errorArgument)) {
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50 | const regexp = new RegExp(errorArgument);
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51 |
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52 | return regexp.test(name);
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53 | }
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54 | return name === errorArgument;
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55 | }
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56 |
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57 | /**
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58 | * Get the parameters of a given function scope.
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59 | * @param {Object} scope The function scope.
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60 | * @returns {array} All parameters of the given scope.
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61 | */
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62 | function getParameters(scope) {
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63 | return scope.variables.filter(variable => variable.defs[0] && variable.defs[0].type === "Parameter");
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64 | }
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65 |
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66 | /**
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67 | * Check to see if we're handling the error object properly.
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68 | * @param {ASTNode} node The AST node to check.
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69 | * @returns {void}
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70 | */
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71 | function checkForError(node) {
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72 | const scope = context.getScope(),
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73 | parameters = getParameters(scope),
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74 | firstParameter = parameters[0];
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75 |
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76 | if (firstParameter && matchesConfiguredErrorName(firstParameter.name)) {
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77 | if (firstParameter.references.length === 0) {
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78 | context.report({ node, message: "Expected error to be handled." });
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79 | }
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80 | }
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81 | }
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82 |
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83 | return {
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84 | FunctionDeclaration: checkForError,
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85 | FunctionExpression: checkForError,
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86 | ArrowFunctionExpression: checkForError
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87 | };
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88 |
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89 | }
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90 | };
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