fix(eslint-plugin): [typedef] allow array/object destructuring in for/of

[a-tarasyuk]

Fixes #1564

[typescript-eslint]

Thanks for the PR, @a-tarasyuk!

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[JoshuaKGoldberg]

Since you requested review, this looks good to me! But I am not a maintainer in this repository and thus my happy opinion means relatively little. 😇

[bradzacher]

idea LGTM.
unless I'm mistaken, this will break on nested destructuring.
tbh I think the rule will just break on that anyways, so it might be good to add a simple validation like "if parent is destructuring then ignore"

[bradzacher]

could you please add a test for nested destructuring

for (const [[key]] of [[['key']]]) {}
for (const [[{ key }]] of [[[{ key: 'value' }]]]) {}

for (const {p1: {p2: { p3 }}} of [{p1: {p2: {p3: 'value'}}}]) {}
for (const {p1: {p2: { p3: [key] }}} of [{p1: {p2: {p3: ['value']}}}]) {}

[bradzacher]

Thinking about it - won't the rule break on these cases anyways?

  const [[[{ key }]]]: [[[{ key: string }]]] = [[[{ key: 'value' }]]]
//         ^^^^^^^    report ❌
//        ^^^^^^^^^   report ❌
//       ^^^^^^^^^^^  report ❌
//      ^^^^^^^^^^^^^ no report ✅ 

[a-tarasyuk]

@bradzacher Added additional tests. About the last case, I think the current implementation doesn't handle that, and the proposed changes will not handle/break that behavior.

[codecov]

Codecov Report

Merging #1570 into master will decrease coverage by <.01%.
The diff coverage is 96.77%.

@@            Coverage Diff             @@
##           master    #1570      +/-   ##
==========================================
- Coverage   95.56%   95.55%   -0.01%     
==========================================
  Files         142      142              
  Lines        6537     6594      +57     
  Branches     1862     1886      +24     
==========================================
+ Hits         6247     6301      +54     
- Misses        105      106       +1     
- Partials      185      187       +2

Impacted Files	Coverage Δ
packages/eslint-plugin/src/rules/ban-types.ts	100% <100%> (ø)	⬆️
...int-plugin/src/rules/strict-boolean-expressions.ts	96.77% <96.42%> (-3.23%)	⬇️

[bradzacher]

LGTM - thanks for this