How to use the jsbi.add function in jsbi

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// you may not use this file except in compliance with the License.
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// .
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// Unless required by applicable law or agreed to in writing, software
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// limitations under the License.

import JSBI from 'jsbi';

const a = JSBI.BigInt(Number.MAX_SAFE_INTEGER);
const b = JSBI.BigInt(12);
console.log(JSBI.add(a, b));
JSBI.BigInt('1');
JSBI.BigInt('34');
JSBI.BigInt('00034');

const JSBigInt = JSBI.BigInt;
JSBigInt(34);
const JSBigInt2 = JSBI['BigInt'];
JSBigInt2(56);
const JSBIadd = JSBI.add;
JSBIadd(7, 8);

JSBI.add(a, b);
JSBI.subtract(a, b);
JSBI.multiply(a, b);
JSBI.divide(a, b);
JSBI.remainder(a, b);

it('> MAX_SAFE_INTEGER: IntSize.BigInt', () => {
            let value = JSBI.add(JSBI.BigInt(Number.MAX_SAFE_INTEGER), JSBI.BigInt(1));
            let reader = ion.makeReader(intToBinaryIonBytes(value));
            assert.equal(IonTypes.INT, reader.next());
            assert.equal(reader.intSize(), IntSize.BigInt);
        });

const a = JSBI.BigInt(Number.MAX_SAFE_INTEGER);
const b = JSBI.BigInt(12);
console.log(JSBI.add(a, b));
JSBI.BigInt('1');
JSBI.BigInt('34');
JSBI.BigInt('00034');

const JSBigInt = JSBI.BigInt;
JSBigInt(34);
const JSBigInt2 = JSBI['BigInt'];
JSBigInt2(56);
const JSBIadd = JSBI.add;
JSBIadd(7, 8);

JSBI.add(a, b);
JSBI.subtract(a, b);
JSBI.multiply(a, b);
JSBI.divide(a, b);
JSBI.remainder(a, b);
JSBI.exponentiate(a, b);
const c = JSBI.unaryMinus(a);
const d = JSBI.bitwiseNot(a);
JSBI.leftShift(a, b);
JSBI.signedRightShift(a, b);
JSBI.bitwiseAnd(a, b);
JSBI.bitwiseOr(a, b);
JSBI.bitwiseXor(a, b);

JSBI.equal(a, b);
JSBI.notEqual(a, b);
JSBI.lessThan(a, b);

it('> MAX_SAFE_INTEGER: IntSize.BigInt', () => {
            let value = JSBI.add(JSBI.BigInt(Number.MAX_SAFE_INTEGER), JSBI.BigInt(1));
            let reader = ion.makeReader(value.toString());
            assert.equal(IonTypes.INT, reader.next());
            assert.equal(reader.intSize(), IntSize.BigInt);
        });