DefinitelyTyped/types/recase/recase-tests.ts

import * as Recase from 'recase';
const recase = Recase.create({exceptions: {FOO: 'foo'}});

const snake = recase.snakeCopy(
    {
        FOO: 1,                  // Exception
        abcXyz: {                // Normal
            _abcXyz: [           // private
                {__abcXyz: 1},   // very private
                {___abcXyz: 1},  // very very private
            ],
        },
    },
);

const camel = recase.camelCopy(
    {
        foo: 1,                   // Exception
        abc_xyz: {                // Normal
            _abc_xyz: [           // private
                {__abc_xyz: 1},   // very private
                {___abc_xyz: 1},  // very very private
            ],
        },
    },
);

recase.snakeCopy(1);
recase.camelCopy(2);
recase.snakeCopy('a');
recase.camelCopy('b');
recase.snakeCopy(['c', '1']);
recase.snakeCopy(['d', '1']);