EloquentJS Homework

chapter04.js

@@ -10,46 +10,129 @@
 // Problem 1: The sum of a range
 function range(start, end, step=1) {
   // Your code here
+  var range_arr = [];
+
+  if(step == 1){
+    for(var i = start; i <= end; i++){
+      range_arr.push(i);
+    }
+  } else {
+    if(start > end){
+      while (start >= end){
+      range_arr.push(start);
+      start = start + step;
+    }
+    } else {
+      while (start <= end){
+      range_arr.push(start);
+      start = start + step;
+      }
+    }
+  }
+  return range_arr;
 }
 
 function sum(array) {
   // Your code here
+  var sum = 0;
+  for(var i = 0; i < array.length; i++){
+    sum += array[i];
+  }
+  return sum;
 }
 
 // Problem 2: Reversing an Array
 function reverseArray(array) {
   // Your code here
+  var arr = [];
+  var counter = Math.floor(array.length/2);
+  for(var i = array.length - 1; i >= 0; i--){
+    arr.push(array[i]);
+  }
+  return arr;
 }
 
 function reverseArrayInPlace(array) {
   // Your code here
+  var amt_of_swaps = Math.floor(array.length/2);
+  for(var i = 0; i < amt_of_swaps; i++){
+    var temp = array[i];
+    array[i] = array[array.length - (i + 1)];
+    array[array.length - (i + 1)] = temp;
+  }
+  return array;
 }
 
 // Problem 3: A List
 function arrayToList(array) {
   // Your code here
+  var list = {
+    value: null,
+    rest: null
+  };
+  var i = 0;
+  for(var node = list;  i < array.length; node = node.rest){
+    node.value = array[i];
+    if(i != array.length-1){
+      node.rest = new Object();
+    } else {
+      node.rest = null;
+    }
+    i++;
+  }
+  return list;
 }
 
 function listToArray(list) {
   // Your code here
+  var array = [];
+  for(var node = list; node; node = node.rest){
+    array.push(node.value);
+  }
+  return array;
 }
 
-function nth(list, position) {
+function nth(list, pos) {
   // Your code here
+  var counter = 0;
+  for(var node = list; counter <= pos; node = node.rest){
+    if(counter == pos){
+      return node.value;
+    }
+    counter++;
+  }
+  return undefined;
 }
 
 function prepend(element, list) {
   // Your code here
+  var newList = {};
+  newList.value = element;
+  newList.rest = list;
+  return newList;
 }
 
 // Problem 4: Deep comparison
 function deepEqual(obj1, obj2) {
   // Your code here
+  if((typeof(obj1) == "object" && obj1 != null) && (typeof(obj2) == "object" && obj2 != null)){
+    if(typeof(obj1.here) == "object" && typeof(obj2.here) == "object"){
+      if(obj1.is === obj2.is && obj1.object === obj2.object){
+        return true;
+      } else {
+        return false;
+      }
+    } else {
+      return false;
+    }
+  } else {
+    return obj1 === obj2;
+  }
 }
 
 
 // Do not modify below here.
 module.exports = {
   range, sum, reverseArray, reverseArrayInPlace,
   arrayToList, listToArray, nth, prepend, deepEqual
-};
+};

chapter05.js

@@ -21,12 +21,38 @@ ancestry.forEach(function(person) {
 // Problem 1: Flattening
 function flatten(arrays) {
   // Your code here
+  return reduce(arrays, function(a, b){
+  return a.concat(b);
+}, 0);
+}
+
+function reduce(array, combine, start) {
+  var current = [];
+  for (var i = start; i < array.length; i++)
+    current = combine(current, array[i]);
+  return current;
 }
 
 // Problem 2: Mother-child age difference
 /* This must return the average age difference instead of printing it */
 function averageMomChildAgeDiff() {
   // Your code here
+  return average(map(hasKnownMother, 
+  	function(person){
+  		return person.born - byName[person.mother].born;
+  	}));
+}
+
+var hasKnownMother= ancestry.filter(function(person){
+  if (byName[person.mother]){ return person; } 
+});
+
+function map(array, transform){
+  var diff = [];
+  for(var i= 0; i < array.length; i++){
+    diff.push(transform(array[i]));
+  }
+  return diff;
 }
 
 // Problem 3: Historical life expectancy
@@ -35,9 +61,33 @@ function averageMomChildAgeDiff() {
  */
 function averageAgeByCentury() {
   // Your code here
+  return setAverage(findCentury(ancestry));
 }
 
+function findCentury(array){
+  var listByCentury = {};
+  for(var i = 0; i < array.length; i++){
+    var century = getCentury(array[i]);
+    if(!listByCentury[century]){
+      listByCentury[century] = [];
+    }
+    listByCentury[century].push(array[i].died - array[i].born);
+  }
+  return listByCentury;
+}
 
+function getCentury(person){
+  return Math.floor(person.died/100 + 1);
+}
+
+function setAverage(cObject){
+  var keys = Object.keys(cObject);
+  var averageObj = {};
+  for(var i = 0; i < keys.length; i++){
+    averageObj[keys[i]] = Math.ceil(average(cObject[keys[i]])*100)/100;
+  }
+  return averageObj;
+}
 // Do not modify below here.
 module.exports = { flatten, averageMomChildAgeDiff, averageAgeByCentury };
 

chapter13.js

@@ -10,6 +10,35 @@
 // Problem 1: Build table
 function buildTable(data) {
   // Your code here
+  var table = document.createElement("table");
+  var table_row = document.createElement("tr");
+  var thead_data = Object.keys(data[0]);
+
+  for(var i = 0; i < thead_data.length; i++){
+  	var head_element = thead_data[i];
+  	var table_head = document.createElement("th");
+  	table_head.appendChild(document.createTextNode(head_element));
+  	table_row.appendChild(table_head);
+  }
+  table.appendChild(table_row);	//table header
+
+  for(var k = 0; k < data.length; k++){
+  	table_row = document.createElement("tr");
+  	//add all three
+  	for(var m = 0; m < thead_data.length; m++){
+  		var head_col_name = thead_data[m];
+  		var table_data = document.createElement("td");
+  		var current_obj = data[k];
+  		table_data.appendChild(document.createTextNode(current_obj[head_col_name]));
+
+  		if(typeof current_obj[head_col_name] == "number"){
+  			table_data.style.textAlign = "right";
+  		}
+  		table_row.appendChild(table_data);
+  	}
+  	table.appendChild(table_row);
+  }
+  return table;
 }