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

   1 /**
   2  * @fileoverview Tests for no-self-assign rule.
   3  * @author Toru Nagashima
   4  */
   5
   6 "use strict";
   7
   8 //------------------------------------------------------------------------------
   9 // Requirements
  10 //------------------------------------------------------------------------------
  11
  12 const rule = require("../../../lib/rules/no-self-assign"),
  13     { RuleTester } = require("../../../lib/rule-tester");
  14
  15 //------------------------------------------------------------------------------
  16 // Tests
  17 //------------------------------------------------------------------------------
  18
  19 const ruleTester = new RuleTester();
  20
  21 ruleTester.run("no-self-assign", rule, {
  22     valid: [
  23         "var a = a",
  24         "a = b",
  25         "a += a",
  26         "a = +a",
  27         "a = [a]",
  28         "a &= a",
  29         "a |= a",
  30         { code: "let a = a", parserOptions: { ecmaVersion: 6 } },
  31         { code: "const a = a", parserOptions: { ecmaVersion: 6 } },
  32         { code: "[a] = a", parserOptions: { ecmaVersion: 6 } },
  33         { code: "[a = 1] = [a]", parserOptions: { ecmaVersion: 6 } },
  34         { code: "[a, b] = [b, a]", parserOptions: { ecmaVersion: 6 } },
  35         { code: "[a,, b] = [, b, a]", parserOptions: { ecmaVersion: 6 } },
  36         { code: "[x, a] = [...x, a]", parserOptions: { ecmaVersion: 6 } },
  37         { code: "[...a] = [...a, 1]", parserOptions: { ecmaVersion: 6 } },
  38         { code: "[a, ...b] = [0, ...b, 1]", parserOptions: { ecmaVersion: 6 } },
  39         { code: "[a, b] = {a, b}", parserOptions: { ecmaVersion: 6 } },
  40         { code: "({a} = a)", parserOptions: { ecmaVersion: 6 } },
  41         { code: "({a = 1} = {a})", parserOptions: { ecmaVersion: 6 } },
  42         { code: "({a: b} = {a})", parserOptions: { ecmaVersion: 6 } },
  43         { code: "({a} = {a: b})", parserOptions: { ecmaVersion: 6 } },
  44         { code: "({a} = {a() {}})", parserOptions: { ecmaVersion: 6 } },
  45         { code: "({a} = {[a]: a})", parserOptions: { ecmaVersion: 6 } },
  46         { code: "({[a]: b} = {[a]: b})", parserOptions: { ecmaVersion: 6 } },
  47         { code: "({'foo': a, 1: a} = {'bar': a, 2: a})", parserOptions: { ecmaVersion: 6 } },
  48         { code: "({a, ...b} = {a, ...b})", parserOptions: { ecmaVersion: 2018 } },
  49         { code: "a.b = a.c", options: [{ props: true }] },
  50         { code: "a.b = c.b", options: [{ props: true }] },
  51         { code: "a.b = a[b]", options: [{ props: true }] },
  52         { code: "a[b] = a.b", options: [{ props: true }] },
  53         { code: "a.b().c = a.b().c", options: [{ props: true }] },
  54         { code: "b().c = b().c", options: [{ props: true }] },
  55         { code: "a.null = a[/(?<zero>0)/]", options: [{ props: true }], parserOptions: { ecmaVersion: 2018 } },
  56         { code: "a[b + 1] = a[b + 1]", options: [{ props: true }] }, // it ignores non-simple computed properties.
  57         {
  58             code: "a.b = a.b",
  59             options: [{ props: false }]
  60         },
  61         {
  62             code: "a.b.c = a.b.c",
  63             options: [{ props: false }]
  64         },
  65         {
  66             code: "a[b] = a[b]",
  67             options: [{ props: false }]
  68         },
  69         {
  70             code: "a['b'] = a['b']",
  71             options: [{ props: false }]
  72         },
  73         {
  74             code: "a[\n    'b'\n] = a[\n    'b'\n]",
  75             options: [{ props: false }]
  76         },
  77         {
  78             code: "this.x = this.y",
  79             options: [{ props: true }]
  80         },
  81         {
  82             code: "this.x = this.x",
  83             options: [{ props: false }]
  84         },
  85         {
  86             code: "class C { #field; foo() { this['#field'] = this.#field; } }",
  87             parserOptions: { ecmaVersion: 2022 }
  88         },
  89         {
  90             code: "class C { #field; foo() { this.#field = this['#field']; } }",
  91             parserOptions: { ecmaVersion: 2022 }
  92         }
  93     ],
  94     invalid: [
  95         { code: "a = a", errors: [{ messageId: "selfAssignment", data: { name: "a" } }] },
  96         { code: "[a] = [a]", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "a" } }] },
  97         { code: "[a, b] = [a, b]", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "a" } }, { messageId: "selfAssignment", data: { name: "b" } }] },
  98         { code: "[a, b] = [a, c]", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "a" } }] },
  99         { code: "[a, b] = [, b]", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "b" } }] },
 100         { code: "[a, ...b] = [a, ...b]", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "a" } }, { messageId: "selfAssignment", data: { name: "b" } }] },
 101         { code: "[[a], {b}] = [[a], {b}]", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "a" } }, { messageId: "selfAssignment", data: { name: "b" } }] },
 102         { code: "({a} = {a})", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "a" } }] },
 103         { code: "({a: b} = {a: b})", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "b" } }] },
 104         { code: "({'a': b} = {'a': b})", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "b" } }] },
 105         { code: "({a: b} = {'a': b})", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "b" } }] },
 106         { code: "({'a': b} = {a: b})", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "b" } }] },
 107         { code: "({1: b} = {1: b})", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "b" } }] },
 108         { code: "({1: b} = {'1': b})", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "b" } }] },
 109         { code: "({'1': b} = {1: b})", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "b" } }] },
 110         { code: "({['a']: b} = {a: b})", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "b" } }] },
 111         { code: "({'a': b} = {[`a`]: b})", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "b" } }] },
 112         { code: "({1: b} = {[1]: b})", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "b" } }] },
 113         { code: "({a, b} = {a, b})", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "a" } }, { messageId: "selfAssignment", data: { name: "b" } }] },
 114         { code: "({a, b} = {b, a})", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "b" } }, { messageId: "selfAssignment", data: { name: "a" } }] },
 115         { code: "({a, b} = {c, a})", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "a" } }] },
 116         { code: "({a: {b}, c: [d]} = {a: {b}, c: [d]})", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "b" } }, { messageId: "selfAssignment", data: { name: "d" } }] },
 117         { code: "({a, b} = {a, ...x, b})", parserOptions: { ecmaVersion: 2018 }, errors: [{ messageId: "selfAssignment", data: { name: "b" } }] },
 118         {
 119             code: "a.b = a.b",
 120             errors: [{ messageId: "selfAssignment", data: { name: "a.b" } }]
 121         },
 122         {
 123             code: "a.b.c = a.b.c",
 124             errors: [{ messageId: "selfAssignment", data: { name: "a.b.c" } }]
 125         },
 126         {
 127             code: "a[b] = a[b]",
 128             errors: [{ messageId: "selfAssignment", data: { name: "a[b]" } }]
 129         },
 130         {
 131             code: "a['b'] = a['b']",
 132             errors: [{ messageId: "selfAssignment", data: { name: "a['b']" } }]
 133         },
 134         {
 135             code: "a[\n    'b'\n] = a[\n    'b'\n]",
 136             errors: [{ messageId: "selfAssignment", data: { name: "a['b']" } }]
 137         },
 138         { code: "a.b = a.b", options: [{ props: true }], errors: [{ messageId: "selfAssignment", data: { name: "a.b" } }] },
 139         { code: "a.b.c = a.b.c", options: [{ props: true }], errors: [{ messageId: "selfAssignment", data: { name: "a.b.c" } }] },
 140         { code: "a[b] = a[b]", options: [{ props: true }], errors: [{ messageId: "selfAssignment", data: { name: "a[b]" } }] },
 141         { code: "a['b'] = a['b']", options: [{ props: true }], errors: [{ messageId: "selfAssignment", data: { name: "a['b']" } }] },
 142         { code: "a[\n    'b'\n] = a[\n    'b'\n]", options: [{ props: true }], errors: [{ messageId: "selfAssignment", data: { name: "a['b']" } }] },
 143         {
 144             code: "this.x = this.x",
 145             options: [{ props: true }],
 146             errors: [{ messageId: "selfAssignment", data: { name: "this.x" } }]
 147         },
 148         { code: "a['/(?<zero>0)/'] = a[/(?<zero>0)/]", options: [{ props: true }], parserOptions: { ecmaVersion: 2018 }, errors: [{ messageId: "selfAssignment", data: { name: "a[/(?<zero>0)/]" } }] },
 149
 150         // Optional chaining
 151         {
 152             code: "(a?.b).c = (a?.b).c",
 153             parserOptions: { ecmaVersion: 2020 },
 154             errors: [{ messageId: "selfAssignment", data: { name: "(a?.b).c" } }]
 155         },
 156         {
 157             code: "a.b = a?.b",
 158             parserOptions: { ecmaVersion: 2020 },
 159             errors: [{ messageId: "selfAssignment", data: { name: "a?.b" } }]
 160         },
 161
 162         // Private members
 163         {
 164             code: "class C { #field; foo() { this.#field = this.#field; } }",
 165             parserOptions: { ecmaVersion: 2022 },
 166             errors: [{ messageId: "selfAssignment", data: { name: "this.#field" } }]
 167         },
 168         {
 169             code: "class C { #field; foo() { [this.#field] = [this.#field]; } }",
 170             parserOptions: { ecmaVersion: 2022 },
 171             errors: [{ messageId: "selfAssignment", data: { name: "this.#field" } }]
 172         },
 173
 174         // logical assignment
 175         {
 176             code: "a &&= a",
 177             parserOptions: { ecmaVersion: 2021 },
 178             errors: [{ messageId: "selfAssignment", data: { name: "a" } }]
 179         },
 180         {
 181             code: "a ||= a",
 182             parserOptions: { ecmaVersion: 2021 },
 183             errors: [{ messageId: "selfAssignment", data: { name: "a" } }]
 184         },
 185         {
 186             code: "a ??= a",
 187             parserOptions: { ecmaVersion: 2021 },
 188             errors: [{ messageId: "selfAssignment", data: { name: "a" } }]
 189         }
 190     ]
 191 });