Ryan Gahl interview with Digital H2O

hash_merge.js

var _ = require('lodash');

var hash1 = {
   key1: 'abc',
   key2: ['123', '222']
};

var hash2 = {
   key2: 'def',
   key4: '456'
};

var hash3 = {
   key5: 'ghi',
   key6: '789'
};

function hash_merge(_hash1, _hash2) {
    var new_hash = {};
    
    for (var p in _hash1) {
        new_hash[p] = _hash1[p];
    }
    
    for (var p in _hash2) {
        if (typeof new_hash[p] !== 'undefined') {
            if (!_.isArray(new_hash[p])) new_hash[p] = [new_hash[p]];
            new_hash[p].push(_hash2[p])
        } else {
            new_hash[p] = _hash2[p];
        }
    }
    
    return new_hash;
}

function merge_n() {
    if (arguments.length === 1) {
        return arguments[0];
    } else {
        
        var new_hash = {};
        
        for (var i = 0; i <= arguments.length - 1; i++) {
            new_hash = hash_merge(new_hash, arguments[i]);
        }
        
        return new_hash;
    }
}

console.log(merge_n(hash1, hash2, hash3));