// Complete the following underscore functions.

// Reference http://underscorejs.org/ for examples.

const keys = (obj) => {

// Retrieve all the names of the object's properties.

// Return the keys as strings in an array.

// Based on http://underscorejs.org/#keys

// console.log('Names: ' + Object.getOwnPropertyNames(obj));

return Object.keys(obj).toString();

};

/*

const testObject = {a: 'asdf', b: 'bnm.', f1: () => {console.log('f1');}}

console.log('testObject keys: '+ keys(testObject));

console.log('String keys: '+ keys(String));

console.log('Array keys: '+ keys(Array));

*/

const values = (obj) => {

// Return all of the values of the object's own properties.

// Ignore functions

// http://underscorejs.org/#values

const arr = [];

const len = Object.values(obj).length;

let i = 0;

for (; i < len; i++) {

if (typeof Object.values(obj)[i] !== 'function') {

arr.push(Object.values(obj)[i]);

}

}

return arr;

};

/*

const testObject = {a: 'asdf', b: 'bnm.', f1: () => {console.log('f1');}}

console.log('testObject values: '+ values(testObject));

console.log('String values: '+ values(String));

console.log('Array values: '+ values(Array));

*/

const mapObject = (obj, cb) => {

// Like map for arrays, but for objects. Transform the value of each property in turn.

// http://underscorejs.org/#mapObject

const len = Object.values(obj).length;

let i = 0;

for (; i < len; i++) {

if (typeof Object.keys(obj)[i] !== 'undefined') {

Object.keys(obj)[i] = cb(Object.keys(obj)[i]);

}

// console.log(Object.keys(obj)[i]);

}

return Object.values(obj);

};

const pairs = (obj) => {

// Convert an object into a list of [key, value] pairs.

// http://underscorejs.org/#pairs

const pairArr = [];

const len = Object.values(obj).length;

let i = 0;

for (; i < len; i++) {

if (typeof Object.keys(obj)[i] !== 'undefined') {

pairArr.push([]);

pairArr[i].push(Object.keys(obj)[i]);

}

if (i === 0) {

pairArr[i][i + 1] = Object.values(obj)[i];

} else {

pairArr[i][i] = Object.values(obj)[i];

}

}

return pairArr;

};

/* Extra credit */

const invert = (obj) => {

// Returns a copy of the object where the keys have become the values and the values the keys.

// Assume that all of the object's values will be unique and string serializable.

// http://underscorejs.org/#invert

};

const defaults = (obj, defaultProps) => {

// Fill in undefined properties that match properties on the `defaultProps` parameter object.

// Return `obj`.

// http://underscorejs.org/#defaults

};

/* eslint-enable no-unused-vars */

module.exports = {

keys,

values,

mapObject,

pairs,

invert,

defaults,

};