[ksa]

тут значение name так нельзя прописать. Они заранее не известны.

Ясно...

const obj = { 
	weight: [
		{ "2021-05-01": 100},
		{ "2021-05-05": "99,9"},
		{ "2021-05-10": 99},
		{ "2021-05-15": "98,5"},
		{ "2021-05-20": 98 },
		{ "2021-05-25": 97.5 },
	],
	weist: [
		{ "2021-05-01": 100},
		{ "2021-05-05": "99,9"},
		{ "2021-05-10": 99},
		{ "2021-05-15": 98},
		{ "2021-05-20": 97},
		{ "2021-05-25": 96.5}
	]
}
let date = []
let total = []
for (let key in obj) {
	let ttl = {
		name: key,
		data: []
	}
	for (let i = 0; i < obj[key].length; i++) {
		const a = Object.keys(obj[key][i])
		date[i] = a[0]
		ttl.data[i] = obj[key][i][a[0]]
	}
	total.push(ttl)
}
alert(JSON.stringify(date) + '\n' + JSON.stringify(total))