Cannot find name 'BigInt'

ERROR in node_modules/buffer/index.d.ts:23:38 - error TS2304: Cannot find name 'BigInt'.

23 readBigUInt64LE(offset: number): BigInt;
~~~~~~
node_modules/buffer/index.d.ts:24:38 - error TS2304: Cannot find name 'BigInt'.

24 readBigUInt64BE(offset: number): BigInt;
~~~~~~
node_modules/buffer/index.d.ts:30:37 - error TS2304: Cannot find name 'BigInt'.

30 readBigInt64LE(offset: number): BigInt;
~~~~~~
node_modules/buffer/index.d.ts:31:37 - error TS2304: Cannot find name 'BigInt'.

31 readBigInt64BE(offset: number): BigInt;
~~~~~~
node_modules/buffer/index.d.ts:45:54 - error TS2304: Cannot find name 'BigInt'.

45 writeBigUInt64LE(value: number, offset: number): BigInt;
~~~~~~
node_modules/buffer/index.d.ts:46:54 - error TS2304: Cannot find name 'BigInt'.

46 writeBigUInt64BE(value: number, offset: number): BigInt;
~~~~~~
node_modules/buffer/index.d.ts:52:53 - error TS2304: Cannot find name 'BigInt'.

52 writeBigInt64LE(value: number, offset: number): BigInt;
~~~~~~
node_modules/buffer/index.d.ts:53:53 - error TS2304: Cannot find name 'BigInt'.

53 writeBigInt64BE(value: number, offset: number): BigInt;
~~~~~~

It is not able to find BigInt and hence throwing the error on project build.
"typescript": "^4.0.3"