function insertDashes(str) {
    result = []
    for (let i = 0; i < str.length - 1; i++) {
        if (isAlpha(str[i]) && isAlpha(str[i+1])) {
            result.push(str[i] + '-')
        } else {
            result.push(str[i])
        }
    }
    result.push(str[str.length - 1])
    return result.join('')
}

function isAlpha(char) {
    return /^[a-zA-Z]$/.test(char)
}


/**
* Test Suite 
*/
describe('insertDashes()', () => {
    it('insert dashes in between chars', () => {
        // arrange
        const value = "aba caba";
        
        // act
        const result = insertDashes(value);

        // log
        console.log("result: ", result);
        
        // assert
        expect(result).toBe("a-b-a c-a-b-a");
    });
});