eslint/tests/lib/rules/no-multi-assign.js

   1 /**
   2  * @fileoverview Tests for no-multi-assign rule.
   3  * @author Stewart Rand
   4  */
   5
   6 "use strict";
   7
   8 //------------------------------------------------------------------------------
   9 // Requirements
  10 //------------------------------------------------------------------------------
  11
  12 const rule = require("../../../lib/rules/no-multi-assign"),
  13     { RuleTester } = require("../../../lib/rule-tester");
  14
  15 //------------------------------------------------------------------------------
  16 // Fixtures
  17 //------------------------------------------------------------------------------
  18
  19 /**
  20  * Returns an error object at the specified line and column
  21  * @private
  22  * @param {int} line line number
  23  * @param {int} column column number
  24  * @param {string} type Type of node
  25  * @returns {Object} Error object
  26  */
  27 function errorAt(line, column, type) {
  28     return {
  29         messageId: "unexpectedChain",
  30         type,
  31         line,
  32         column
  33     };
  34 }
  35
  36
  37 //------------------------------------------------------------------------------
  38 // Tests
  39 //------------------------------------------------------------------------------
  40
  41 const ruleTester = new RuleTester();
  42
  43 ruleTester.run("no-mutli-assign", rule, {
  44     valid: [
  45         "var a, b, c,\nd = 0;",
  46         "var a = 1; var b = 2; var c = 3;\nvar d = 0;",
  47         "var a = 1 + (b === 10 ? 5 : 4);",
  48         { code: "const a = 1, b = 2, c = 3;", parserOptions: { ecmaVersion: 6 } },
  49         { code: "const a = 1;\nconst b = 2;\n const c = 3;", parserOptions: { ecmaVersion: 6 } },
  50         "for(var a = 0, b = 0;;){}",
  51         { code: "for(let a = 0, b = 0;;){}", parserOptions: { ecmaVersion: 6 } },
  52         { code: "for(const a = 0, b = 0;;){}", parserOptions: { ecmaVersion: 6 } },
  53         { code: "export let a, b;", parserOptions: { ecmaVersion: 6, sourceType: "module" } },
  54         { code: "export let a,\n b = 0;", parserOptions: { ecmaVersion: 6, sourceType: "module" } }
  55     ],
  56
  57     invalid: [
  58         {
  59             code: "var a = b = c;",
  60             errors: [
  61                 errorAt(1, 9, "AssignmentExpression")
  62             ]
  63         },
  64         {
  65             code: "var a = b = c = d;",
  66             errors: [
  67                 errorAt(1, 9, "AssignmentExpression"),
  68                 errorAt(1, 13, "AssignmentExpression")
  69             ]
  70         },
  71         {
  72             code: "let foo = bar = cee = 100;",
  73             parserOptions: { ecmaVersion: 6 },
  74             errors: [
  75                 errorAt(1, 11, "AssignmentExpression"),
  76                 errorAt(1, 17, "AssignmentExpression")
  77             ]
  78         },
  79         {
  80             code: "a=b=c=d=e",
  81             errors: [
  82                 errorAt(1, 3, "AssignmentExpression"),
  83                 errorAt(1, 5, "AssignmentExpression"),
  84                 errorAt(1, 7, "AssignmentExpression")
  85             ]
  86         },
  87         {
  88             code: "a=b=c",
  89             errors: [
  90                 errorAt(1, 3, "AssignmentExpression")
  91             ]
  92         },
  93
  94         {
  95             code: "a\n=b\n=c",
  96             errors: [
  97                 errorAt(2, 2, "AssignmentExpression")
  98             ]
  99         },
 100
 101         {
 102             code: "var a = (b) = (((c)))",
 103             errors: [
 104                 errorAt(1, 9, "AssignmentExpression")
 105             ]
 106         },
 107
 108         {
 109             code: "var a = ((b)) = (c)",
 110             errors: [
 111                 errorAt(1, 9, "AssignmentExpression")
 112             ]
 113         },
 114
 115         {
 116             code: "var a = b = ( (c * 12) + 2)",
 117             errors: [
 118                 errorAt(1, 9, "AssignmentExpression")
 119             ]
 120         },
 121
 122         {
 123             code: "var a =\n((b))\n = (c)",
 124             errors: [
 125                 errorAt(2, 1, "AssignmentExpression")
 126             ]
 127         },
 128
 129         {
 130             code: "a = b = '=' + c + 'foo';",
 131             errors: [
 132                 errorAt(1, 5, "AssignmentExpression")
 133             ]
 134         },
 135         {
 136             code: "a = b = 7 * 12 + 5;",
 137             errors: [
 138                 errorAt(1, 5, "AssignmentExpression")
 139             ]
 140         }
 141     ]
 142 });