Add %_ format to skip a parameter in test.each/for

[hermit99]

Clear and concise description of the problem

The current formats do not provide a way to skip some parameters in the test name output when test data is array.

For example,

it.each([
  ['row1', { ...params1 }, 'expected1'],
  ['row2', { ...params2 }, 'expected2'],
])('%#. %s => %s %s', (row, param, expected) => tester())

// This will return
// 0. row1 => {...params1} expected1
// 1. row2 => {...params2} expected2
// The middle params is always displayed

Although we can work around

1. by using object for each test data, but that's much more verbose
2. by adjusting the order of parameters, e.g. make the 'expected' before the actual params, but that doesn't flow elegantly either.

I'm hoping to have more flexibility to control which param is shown in test name.

Suggested solution

Format %_ indicates that parameter is skipped in the test name

it.each([
  ['row1', { ...params1 }, 'expected1'],
  ['row2', { ...params2 }, 'expected2'],
])('%#. %s => %_%s', (row, param, expected) => tester())

// This will return
// 0. row1 => expected1
// 1. row2 => expected2
// The middle params is omitted

Alternative

No response

Additional context

No response

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that request the same feature to avoid creating a duplicate.

[hi-ogawa]

How about supporting element index of array like object? https://stackblitz.com/edit/vitest-dev-vitest-wvqa9r6r?file=test%2Fbasic.test.ts

// this works
it.each([
  { 0: 'row1', 1: {}, 2: 'expected1' },
  { 0: 'row2', 1: {}, 2: 'expected2' },
])('%#. $0 => $2', () => {});
// ✓ 0. 'row1' => 'expected1'
// ✓ 1. 'row2' => 'expected2'


// but this doesn't currently
it.each([
  ['row1', {}, 'expected1'],
  ['row2', {}, 'expected2'],
])('%#. $0 => $2', () => {});
// ✓ 0. $0 => $2
// ✓ 1. $0 => $2

(Currently object key $x gets quoted but that'll be fixed by #5946)