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         { code: "let a = a", parserOptions: { ecmaVersion: 6 } },
  29         { code: "const a = a", parserOptions: { ecmaVersion: 6 } },
  30         { code: "[a] = a", parserOptions: { ecmaVersion: 6 } },
  31         { code: "[a = 1] = [a]", parserOptions: { ecmaVersion: 6 } },
  32         { code: "[a, b] = [b, a]", parserOptions: { ecmaVersion: 6 } },
  33         { code: "[a,, b] = [, b, a]", parserOptions: { ecmaVersion: 6 } },
  34         { code: "[x, a] = [...x, a]", parserOptions: { ecmaVersion: 6 } },
  35         { code: "[...a] = [...a, 1]", parserOptions: { ecmaVersion: 6 } },
  36         { code: "[a, ...b] = [0, ...b, 1]", parserOptions: { ecmaVersion: 6 } },
  37         { code: "[a, b] = {a, b}", parserOptions: { ecmaVersion: 6 } },
  38         { code: "({a} = a)", parserOptions: { ecmaVersion: 6 } },
  39         { code: "({a = 1} = {a})", parserOptions: { ecmaVersion: 6 } },
  40         { code: "({a: b} = {a})", parserOptions: { ecmaVersion: 6 } },
  41         { code: "({a} = {a: b})", parserOptions: { ecmaVersion: 6 } },
  42         { code: "({a} = {a() {}})", parserOptions: { ecmaVersion: 6 } },
  43         { code: "({a} = {[a]: a})", parserOptions: { ecmaVersion: 6 } },
  44         { code: "({[a]: b} = {[a]: b})", parserOptions: { ecmaVersion: 6 } },
  45         { code: "({'foo': a, 1: a} = {'bar': a, 2: a})", parserOptions: { ecmaVersion: 6 } },
  46         { code: "({a, ...b} = {a, ...b})", parserOptions: { ecmaVersion: 2018 } },
  47         { code: "a.b = a.c", options: [{ props: true }] },
  48         { code: "a.b = c.b", options: [{ props: true }] },
  49         { code: "a.b = a[b]", options: [{ props: true }] },
  50         { code: "a[b] = a.b", options: [{ props: true }] },
  51         { code: "a.b().c = a.b().c", options: [{ props: true }] },
  52         { code: "b().c = b().c", options: [{ props: true }] },
  53         { code: "a.null = a[/(?<zero>0)/]", options: [{ props: true }], parserOptions: { ecmaVersion: 2018 } },
  54         { code: "a[b + 1] = a[b + 1]", options: [{ props: true }] }, // it ignores non-simple computed properties.
  55         {
  56             code: "a.b = a.b",
  57             options: [{ props: false }]
  58         },
  59         {
  60             code: "a.b.c = a.b.c",
  61             options: [{ props: false }]
  62         },
  63         {
  64             code: "a[b] = a[b]",
  65             options: [{ props: false }]
  66         },
  67         {
  68             code: "a['b'] = a['b']",
  69             options: [{ props: false }]
  70         },
  71         {
  72             code: "a[\n    'b'\n] = a[\n    'b'\n]",
  73             options: [{ props: false }]
  74         },
  75         {
  76             code: "this.x = this.y",
  77             options: [{ props: true }]
  78         },
  79         {
  80             code: "this.x = this.x",
  81             options: [{ props: false }]
  82         },
  83         {
  84             code: "class C { #field; foo() { this['#field'] = this.#field; } }",
  85             parserOptions: { ecmaVersion: 2022 }
  86         },
  87         {
  88             code: "class C { #field; foo() { this.#field = this['#field']; } }",
  89             parserOptions: { ecmaVersion: 2022 }
  90         }
  91     ],
  92     invalid: [
  93         { code: "a = a", errors: [{ messageId: "selfAssignment", data: { name: "a" } }] },
  94         { code: "[a] = [a]", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "a" } }] },
  95         { code: "[a, b] = [a, b]", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "a" } }, { messageId: "selfAssignment", data: { name: "b" } }] },
  96         { code: "[a, b] = [a, c]", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "a" } }] },
  97         { code: "[a, b] = [, b]", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "b" } }] },
  98         { code: "[a, ...b] = [a, ...b]", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "a" } }, { messageId: "selfAssignment", data: { name: "b" } }] },
  99         { code: "[[a], {b}] = [[a], {b}]", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "a" } }, { messageId: "selfAssignment", data: { name: "b" } }] },
 100         { code: "({a} = {a})", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "a" } }] },
 101         { code: "({a: b} = {a: b})", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "b" } }] },
 102         { code: "({'a': b} = {'a': b})", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "b" } }] },
 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: "({1: b} = {1: b})", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "b" } }] },
 106         { code: "({1: b} = {'1': 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: "({['a']: b} = {a: b})", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "b" } }] },
 109         { code: "({'a': b} = {[`a`]: b})", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "b" } }] },
 110         { code: "({1: b} = {[1]: b})", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "b" } }] },
 111         { code: "({a, b} = {a, b})", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "a" } }, { messageId: "selfAssignment", data: { name: "b" } }] },
 112         { code: "({a, b} = {b, a})", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "b" } }, { messageId: "selfAssignment", data: { name: "a" } }] },
 113         { code: "({a, b} = {c, a})", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "a" } }] },
 114         { code: "({a: {b}, c: [d]} = {a: {b}, c: [d]})", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "selfAssignment", data: { name: "b" } }, { messageId: "selfAssignment", data: { name: "d" } }] },
 115         { code: "({a, b} = {a, ...x, b})", parserOptions: { ecmaVersion: 2018 }, errors: [{ messageId: "selfAssignment", data: { name: "b" } }] },
 116         {
 117             code: "a.b = a.b",
 118             errors: [{ messageId: "selfAssignment", data: { name: "a.b" } }]
 119         },
 120         {
 121             code: "a.b.c = a.b.c",
 122             errors: [{ messageId: "selfAssignment", data: { name: "a.b.c" } }]
 123         },
 124         {
 125             code: "a[b] = a[b]",
 126             errors: [{ messageId: "selfAssignment", data: { name: "a[b]" } }]
 127         },
 128         {
 129             code: "a['b'] = a['b']",
 130             errors: [{ messageId: "selfAssignment", data: { name: "a['b']" } }]
 131         },
 132         {
 133             code: "a[\n    'b'\n] = a[\n    'b'\n]",
 134             errors: [{ messageId: "selfAssignment", data: { name: "a['b']" } }]
 135         },
 136         { code: "a.b = a.b", options: [{ props: true }], errors: [{ messageId: "selfAssignment", data: { name: "a.b" } }] },
 137         { code: "a.b.c = a.b.c", options: [{ props: true }], errors: [{ messageId: "selfAssignment", data: { name: "a.b.c" } }] },
 138         { code: "a[b] = a[b]", options: [{ props: true }], errors: [{ messageId: "selfAssignment", data: { name: "a[b]" } }] },
 139         { code: "a['b'] = a['b']", options: [{ props: true }], errors: [{ messageId: "selfAssignment", data: { name: "a['b']" } }] },
 140         { code: "a[\n    'b'\n] = a[\n    'b'\n]", options: [{ props: true }], errors: [{ messageId: "selfAssignment", data: { name: "a['b']" } }] },
 141         {
 142             code: "this.x = this.x",
 143             options: [{ props: true }],
 144             errors: [{ messageId: "selfAssignment", data: { name: "this.x" } }]
 145         },
 146         { code: "a['/(?<zero>0)/'] = a[/(?<zero>0)/]", options: [{ props: true }], parserOptions: { ecmaVersion: 2018 }, errors: [{ messageId: "selfAssignment", data: { name: "a[/(?<zero>0)/]" } }] },
 147
 148         // Optional chaining
 149         {
 150             code: "(a?.b).c = (a?.b).c",
 151             parserOptions: { ecmaVersion: 2020 },
 152             errors: [{ messageId: "selfAssignment", data: { name: "(a?.b).c" } }]
 153         },
 154         {
 155             code: "a.b = a?.b",
 156             parserOptions: { ecmaVersion: 2020 },
 157             errors: [{ messageId: "selfAssignment", data: { name: "a?.b" } }]
 158         },
 159
 160         // Private members
 161         {
 162             code: "class C { #field; foo() { this.#field = this.#field; } }",
 163             parserOptions: { ecmaVersion: 2022 },
 164             errors: [{ messageId: "selfAssignment", data: { name: "this.#field" } }]
 165         },
 166         {
 167             code: "class C { #field; foo() { [this.#field] = [this.#field]; } }",
 168             parserOptions: { ecmaVersion: 2022 },
 169             errors: [{ messageId: "selfAssignment", data: { name: "this.#field" } }]
 170         }
 171     ]
 172 });