How to use variables for custom fields inside NetSuite search.lookupFields and record.submitFields()

In NetSuite script functions search.lookupFields and record.submitFields() there is an option to pass multiple custom field scriptids as parameters.

e.g:

let fieldLookUp = search.lookupFields({
    type: search.Type.SALES_ORDER,
    id: '101',
    columns: ['custbody_1', 'custbody_2', 'custbody_3', 'custbody_4']
});
record.submitFields({
    type: record.Type.SALES_ORDER,
    id: 101,
    values: {
        'custbody_1': 'Hello from custom field',
        'custbody_2': 'Test',
        'custbody_3': 254,
        'custbody_4': '1'
    }
});

But we cannot use a variable name instead of field IDs here. If we directly pass variable replacing the field ID, it will return script error. As a fix, we can pass each variable inside square brackets.

e.g:

const CUSTOM_FIELDS_OBJ = {
  CUST_BODY1: 'custbody_1',
  CUST_BODY2: 'custbody_2',
  CUST_BODY3: 'custbody_3',
  CUST_BODY4: 'custbody_4',
}
let fieldLookUp = search.lookupFields({
    type: search.Type.SALES_ORDER,
    id: '101',
    columns: [
    [CUSTOM_FIELDS_OBJ.CUST_BODY1],
    [CUSTOM_FIELDS_OBJ.CUST_BODY2],
    [CUSTOM_FIELDS_OBJ.CUST_BODY3],
    [CUSTOM_FIELDS_OBJ.CUST_BODY4]
    ]
});
record.submitFields({
    type: record.Type.SALES_ORDER,
    id: 101,
    values: {
        [CUSTOM_FIELDS_OBJ.CUST_BODY1]: 'Hello from custom field',
        [CUSTOM_FIELDS_OBJ.CUST_BODY2]: 'Test',
        [CUSTOM_FIELDS_OBJ.CUST_BODY3]: 254,
        [CUSTOM_FIELDS_OBJ.CUST_BODY4]: '1'
    }
});