Code:

import _ from 'lodash';

const BillTermTextMap = {
  0: "0m",
  1: "1m",
} as const;

type BillTerm = typeof BillTermTextMap;
type BillTermValues = BillTerm[keyof BillTerm];
type BillTermKey = keyof BillTerm;

type MarketReportDTO = {
  amount: number;
  billTerm: BillTermKey;
}

type TableRecord = { title: string } & Record<BillTermValues, MarketReportDTO>;

const marketReportDTOs: MarketReportDTO[] = [{ amount: 1, billTerm: 0 }, { amount: 2, billTerm: 1 }]
const tableRecord: TableRecord = Object.assign({ title: 'test' }, _.keyBy(marketReportDTOs, o => BillTermTextMap[o.billTerm]))

console.log('tableRecord: ', tableRecord)

// { title: 'test', '0m': { amount: 1, billTerm: 0 }, '1m': { amount: 2, billTerm: 1 } }

Got error:

Type '{ title: string; }' is not assignable to type 'TableRecord'.
  Type '{ title: string; }' is missing the following properties from type 'Record<BillTermValues, MarketReportDTO>': "0m", "1m", "2m", "3m", and 3 more.(2322)

I am not sure it’s because the spread operator or the return type of the _.keyBy() function.

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