eslint/tests/lib/rules/no-unneeded-ternary.js

   1 /**
   2  * @fileoverview Tests for no-unneeded-ternary rule.
   3  * @author Gyandeep Singh
   4  */
   5
   6 "use strict";
   7
   8 //------------------------------------------------------------------------------
   9 // Requirements
  10 //------------------------------------------------------------------------------
  11
  12 const rule = require("../../../lib/rules/no-unneeded-ternary"),
  13     { RuleTester } = require("../../../lib/rule-tester");
  14
  15 //------------------------------------------------------------------------------
  16 // Tests
  17 //------------------------------------------------------------------------------
  18
  19 const ruleTester = new RuleTester();
  20
  21 ruleTester.run("no-unneeded-ternary", rule, {
  22     valid: [
  23         "config.newIsCap = config.newIsCap !== false",
  24         "var a = x === 2 ? 'Yes' : 'No';",
  25         "var a = x === 2 ? true : 'No';",
  26         "var a = x === 2 ? 'Yes' : false;",
  27         "var a = x === 2 ? 'true' : 'false';",
  28         "var a = foo ? foo : bar;",
  29         "var value = 'a';var canSet = true;var result = value || (canSet ? 'unset' : 'can not set')",
  30         "var a = foo ? bar : foo;",
  31         "foo ? bar : foo;",
  32         "var a = f(x ? x : 1)",
  33         "f(x ? x : 1);",
  34         "foo ? foo : bar;",
  35         "var a = foo ? 'Yes' : foo;",
  36         {
  37             code: "var a = foo ? 'Yes' : foo;",
  38             options: [{ defaultAssignment: false }]
  39         },
  40         {
  41             code: "var a = foo ? bar : foo;",
  42             options: [{ defaultAssignment: false }]
  43         },
  44         {
  45             code: "foo ? bar : foo;",
  46             options: [{ defaultAssignment: false }]
  47         }
  48     ],
  49     invalid: [
  50         {
  51             code: "var a = x === 2 ? true : false;",
  52             output: "var a = x === 2;",
  53             errors: [{
  54                 messageId: "unnecessaryConditionalExpression",
  55                 type: "ConditionalExpression",
  56                 line: 1,
  57                 column: 19
  58             }]
  59         },
  60         {
  61             code: "var a = x >= 2 ? true : false;",
  62             output: "var a = x >= 2;",
  63             errors: [{
  64                 messageId: "unnecessaryConditionalExpression",
  65                 type: "ConditionalExpression",
  66                 line: 1,
  67                 column: 18
  68             }]
  69         },
  70         {
  71             code: "var a = x ? true : false;",
  72             output: "var a = !!x;",
  73             errors: [{
  74                 messageId: "unnecessaryConditionalExpression",
  75                 type: "ConditionalExpression",
  76                 line: 1,
  77                 column: 13
  78             }]
  79         },
  80         {
  81             code: "var a = x === 1 ? false : true;",
  82             output: "var a = x !== 1;",
  83             errors: [{
  84                 messageId: "unnecessaryConditionalExpression",
  85                 type: "ConditionalExpression",
  86                 line: 1,
  87                 column: 19
  88             }]
  89         },
  90         {
  91             code: "var a = x != 1 ? false : true;",
  92             output: "var a = x == 1;",
  93             errors: [{
  94                 messageId: "unnecessaryConditionalExpression",
  95                 type: "ConditionalExpression",
  96                 line: 1,
  97                 column: 18
  98             }]
  99         },
 100         {
 101             code: "var a = foo() ? false : true;",
 102             output: "var a = !foo();",
 103             errors: [{
 104                 messageId: "unnecessaryConditionalExpression",
 105                 type: "ConditionalExpression",
 106                 line: 1,
 107                 column: 17
 108             }]
 109         },
 110         {
 111             code: "var a = !foo() ? false : true;",
 112             output: "var a = !!foo();",
 113             errors: [{
 114                 messageId: "unnecessaryConditionalExpression",
 115                 type: "ConditionalExpression",
 116                 line: 1,
 117                 column: 18
 118             }]
 119         },
 120         {
 121             code: "var a = foo + bar ? false : true;",
 122             output: "var a = !(foo + bar);",
 123             errors: [{
 124                 messageId: "unnecessaryConditionalExpression",
 125                 type: "ConditionalExpression",
 126                 line: 1,
 127                 column: 21
 128             }]
 129         },
 130         {
 131             code: "var a = x instanceof foo ? false : true;",
 132             output: "var a = !(x instanceof foo);",
 133             errors: [{
 134                 messageId: "unnecessaryConditionalExpression",
 135                 type: "ConditionalExpression",
 136                 line: 1,
 137                 column: 28
 138             }]
 139         },
 140         {
 141             code: "var a = foo ? false : false;",
 142             output: "var a = false;",
 143             errors: [{
 144                 messageId: "unnecessaryConditionalExpression",
 145                 type: "ConditionalExpression",
 146                 line: 1,
 147                 column: 15
 148             }]
 149         },
 150         {
 151             code: "var a = foo() ? false : false;",
 152             output: null,
 153             errors: [{
 154                 messageId: "unnecessaryConditionalExpression",
 155                 type: "ConditionalExpression",
 156                 line: 1,
 157                 column: 17
 158             }]
 159         },
 160         {
 161             code: "var a = x instanceof foo ? true : false;",
 162             output: "var a = x instanceof foo;",
 163             errors: [{
 164                 messageId: "unnecessaryConditionalExpression",
 165                 type: "ConditionalExpression",
 166                 line: 1,
 167                 column: 28
 168             }]
 169         },
 170         {
 171             code: "var a = !foo ? true : false;",
 172             output: "var a = !foo;",
 173             errors: [{
 174                 messageId: "unnecessaryConditionalExpression",
 175                 type: "ConditionalExpression",
 176                 line: 1,
 177                 column: 16
 178             }]
 179         },
 180         {
 181             code: `
 182                 var value = 'a'
 183                 var canSet = true
 184                 var result = value ? value : canSet ? 'unset' : 'can not set'
 185             `,
 186             output: `
 187                 var value = 'a'
 188                 var canSet = true
 189                 var result = value || (canSet ? 'unset' : 'can not set')
 190             `,
 191             options: [{ defaultAssignment: false }],
 192             errors: [{
 193                 messageId: "unnecessaryConditionalAssignment",
 194                 type: "ConditionalExpression",
 195                 line: 4,
 196                 column: 38
 197             }]
 198         },
 199         {
 200             code: "foo ? foo : (bar ? baz : qux)",
 201             output: "foo || (bar ? baz : qux)",
 202             options: [{ defaultAssignment: false }],
 203             errors: [{
 204                 messageId: "unnecessaryConditionalAssignment",
 205                 type: "ConditionalExpression",
 206                 line: 1,
 207                 column: 7
 208             }]
 209         },
 210         {
 211             code: "function* fn() { foo ? foo : yield bar }",
 212             output: "function* fn() { foo || (yield bar) }",
 213             options: [{ defaultAssignment: false }],
 214             parserOptions: { ecmaVersion: 6 },
 215             errors: [{
 216                 messageId: "unnecessaryConditionalAssignment",
 217                 type: "ConditionalExpression",
 218                 line: 1,
 219                 column: 24
 220             }]
 221         },
 222         {
 223             code: "var a = foo ? foo : 'No';",
 224             output: "var a = foo || 'No';",
 225             options: [{ defaultAssignment: false }],
 226             errors: [{
 227                 messageId: "unnecessaryConditionalAssignment",
 228                 type: "ConditionalExpression",
 229                 line: 1,
 230                 column: 15
 231             }]
 232         },
 233         {
 234             code: "var a = ((foo)) ? (((((foo))))) : ((((((((((((((bar))))))))))))));",
 235             output: "var a = ((foo)) || ((((((((((((((bar))))))))))))));",
 236             options: [{ defaultAssignment: false }],
 237             errors: [{
 238                 messageId: "unnecessaryConditionalAssignment",
 239                 type: "ConditionalExpression",
 240                 line: 1,
 241                 column: 24
 242             }]
 243         },
 244         {
 245             code: "var a = b ? b : c => c;",
 246             output: "var a = b || (c => c);",
 247             options: [{ defaultAssignment: false }],
 248             parserOptions: { ecmaVersion: 2015 },
 249             errors: [{
 250                 messageId: "unnecessaryConditionalAssignment",
 251                 type: "ConditionalExpression",
 252                 line: 1,
 253                 column: 13
 254             }]
 255         },
 256         {
 257             code: "var a = b ? b : c = 0;",
 258             output: "var a = b || (c = 0);",
 259             options: [{ defaultAssignment: false }],
 260             parserOptions: { ecmaVersion: 2015 },
 261             errors: [{
 262                 messageId: "unnecessaryConditionalAssignment",
 263                 type: "ConditionalExpression",
 264                 line: 1,
 265                 column: 13
 266             }]
 267         },
 268         {
 269             code: "var a = b ? b : (c => c);",
 270             output: "var a = b || (c => c);",
 271             options: [{ defaultAssignment: false }],
 272             parserOptions: { ecmaVersion: 2015 },
 273             errors: [{
 274                 messageId: "unnecessaryConditionalAssignment",
 275                 type: "ConditionalExpression",
 276                 line: 1,
 277                 column: 13
 278             }]
 279         },
 280         {
 281             code: "var a = b ? b : (c = 0);",
 282             output: "var a = b || (c = 0);",
 283             options: [{ defaultAssignment: false }],
 284             parserOptions: { ecmaVersion: 2015 },
 285             errors: [{
 286                 messageId: "unnecessaryConditionalAssignment",
 287                 type: "ConditionalExpression",
 288                 line: 1,
 289                 column: 13
 290             }]
 291         },
 292         {
 293             code: "var a = b ? b : (c) => (c);",
 294             output: "var a = b || ((c) => (c));",
 295             options: [{ defaultAssignment: false }],
 296             parserOptions: { ecmaVersion: 2015 },
 297             errors: [{
 298                 messageId: "unnecessaryConditionalAssignment",
 299                 type: "ConditionalExpression",
 300                 line: 1,
 301                 column: 13
 302             }]
 303         },
 304         {
 305             code: "var a = b ? b : c, d; // this is ((b ? b : c), (d))",
 306             output: "var a = b || c, d; // this is ((b ? b : c), (d))",
 307             options: [{ defaultAssignment: false }],
 308             parserOptions: { ecmaVersion: 2015 },
 309             errors: [{
 310                 messageId: "unnecessaryConditionalAssignment",
 311                 type: "ConditionalExpression",
 312                 line: 1,
 313                 column: 13
 314             }]
 315         },
 316         {
 317             code: "var a = b ? b : (c, d);",
 318             output: "var a = b || (c, d);",
 319             options: [{ defaultAssignment: false }],
 320             parserOptions: { ecmaVersion: 2015 },
 321             errors: [{
 322                 messageId: "unnecessaryConditionalAssignment",
 323                 type: "ConditionalExpression",
 324                 line: 1,
 325                 column: 13
 326             }]
 327         },
 328         {
 329             code: "f(x ? x : 1);",
 330             output: "f(x || 1);",
 331             options: [{ defaultAssignment: false }],
 332             errors: [{
 333                 messageId: "unnecessaryConditionalAssignment",
 334                 type: "ConditionalExpression",
 335                 line: 1,
 336                 column: 7
 337             }]
 338         },
 339         {
 340             code: "x ? x : 1;",
 341             output: "x || 1;",
 342             options: [{ defaultAssignment: false }],
 343             errors: [{
 344                 messageId: "unnecessaryConditionalAssignment",
 345                 type: "ConditionalExpression",
 346                 line: 1,
 347                 column: 5
 348             }]
 349         },
 350         {
 351             code: "var a = foo ? foo : bar;",
 352             output: "var a = foo || bar;",
 353             options: [{ defaultAssignment: false }],
 354             errors: [{
 355                 messageId: "unnecessaryConditionalAssignment",
 356                 type: "ConditionalExpression",
 357                 line: 1,
 358                 column: 15
 359             }]
 360         }
 361     ]
 362 });