#2025 array of querystring without number

[alfa-jpn]

Description

This is WIP about issue #2025.

Motivation and Context

Please reference issue #2025.

How Has This Been Tested?

var querystring = m.buildQueryString({a: ["hello", "world"]})
// querystring is "a[]=hello&a[]=world"

m.parseQueryString("a[]=hello&a[]=world")
// data is {a: ["hello", "world"]}

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [x] Breaking change (fix or feature that would cause existing functionality to change)
  • remove index from array querystring
  • unsupport nest array ex) { a: [["x"], ["y"]] } // a[0][0]=x&a[1][0]=y

Checklist:

• [x] My code follows the code style of this project.
• [x] My change requires a change to the documentation.
• [x] I have updated the documentation accordingly.
• [x] I have read the CONTRIBUTING document.
• [x] I have added tests to cover my changes.
• [x] All new and existing tests passed.
• [x] I have updated docs/change-log.md

[StephanHoyer]

@alfa-jpn would you mind rebasing your change onto the current version? I think we are ready to merge this now