JSFiddle - React, Tailwind, and code Playground

JavaScript

var a = [
  [
		{a: 'a',
     b: 'b'
    },
    {a: 'aa',
     b: 'bb'
    },
    {a: 'a',
     b: 'b'
    }
  ],
  [
		{a: 'a',
     b: 'b'
    },
    {a: 'a',
     b: 'b'
    },
    {a: 'a',
     b: 'b'
    }
  ],
  [
		{a: 'a',
     b: 'b'
    },
    {a: 'a',
     b: 'b'
    },
    {a: 'a',
     b: 'b'
    }
  ]
]
var b = [];
a.map(e => {
	return b.push(...e)
})

console.log(b)