1 | /**
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2 | * @fileoverview Rule to flag when a function has too many parameters
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3 | * @author Ilya Volodin
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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 | // Requirements
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10 | //------------------------------------------------------------------------------
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11 |
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12 | const lodash = require("lodash");
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13 |
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14 | const astUtils = require("./utils/ast-utils");
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15 |
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16 | //------------------------------------------------------------------------------
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17 | // Rule Definition
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18 | //------------------------------------------------------------------------------
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19 |
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20 | module.exports = {
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21 | meta: {
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22 | type: "suggestion",
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23 |
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24 | docs: {
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25 | description: "enforce a maximum number of parameters in function definitions",
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26 | category: "Stylistic Issues",
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27 | recommended: false,
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28 | url: "https://eslint.org/docs/rules/max-params"
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29 | },
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30 |
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31 | schema: [
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32 | {
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33 | oneOf: [
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34 | {
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35 | type: "integer",
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36 | minimum: 0
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37 | },
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38 | {
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39 | type: "object",
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40 | properties: {
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41 | maximum: {
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42 | type: "integer",
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43 | minimum: 0
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44 | },
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45 | max: {
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46 | type: "integer",
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47 | minimum: 0
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48 | }
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49 | },
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50 | additionalProperties: false
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51 | }
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52 | ]
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53 | }
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54 | ],
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55 | messages: {
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56 | exceed: "{{name}} has too many parameters ({{count}}). Maximum allowed is {{max}}."
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57 | }
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58 | },
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59 |
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60 | create(context) {
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61 | const sourceCode = context.getSourceCode();
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62 | const option = context.options[0];
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63 | let numParams = 3;
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64 |
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65 | if (
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66 | typeof option === "object" &&
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67 | (Object.prototype.hasOwnProperty.call(option, "maximum") || Object.prototype.hasOwnProperty.call(option, "max"))
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68 | ) {
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69 | numParams = option.maximum || option.max;
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70 | }
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71 | if (typeof option === "number") {
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72 | numParams = option;
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73 | }
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74 |
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75 | /**
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76 | * Checks a function to see if it has too many parameters.
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77 | * @param {ASTNode} node The node to check.
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78 | * @returns {void}
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79 | * @private
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80 | */
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81 | function checkFunction(node) {
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82 | if (node.params.length > numParams) {
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83 | context.report({
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84 | loc: astUtils.getFunctionHeadLoc(node, sourceCode),
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85 | node,
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86 | messageId: "exceed",
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87 | data: {
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88 | name: lodash.upperFirst(astUtils.getFunctionNameWithKind(node)),
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89 | count: node.params.length,
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90 | max: numParams
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91 | }
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92 | });
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93 | }
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94 | }
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95 |
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96 | return {
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97 | FunctionDeclaration: checkFunction,
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98 | ArrowFunctionExpression: checkFunction,
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99 | FunctionExpression: checkFunction
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100 | };
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101 |
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102 | }
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103 | };
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