What problem does this feature solve?

As we can push router with query like router.push({query: {a: 1, b: 2}})

but it's not convenient while I just want to add a condition.

I do this as the followed code to get query string ?a=1&b=2&c=3:

import _ from 'lodash'
let query = _.cloneDeep(router.currentRoute.query)
query.c = 3
router.push(query)

What does the proposed API look like?

router.pushQueryParams({c: 3})