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js06/js06.md

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+### sort
+
+```javascript
+var persons = [
+	{name: "Иван", age: 17},
+	{name: "Мария", age: 35},
+	{name: "Алексей", age: 73},
+	{name: "Яков", age: 12},
+]
+
+function sort(array, key, bool){
+	function sortType(a,b){
+		if(bool === undefined)
+			bool = true;
+		if(bool){
+			if(a[key] > b[key])
+				return 1
+			else
+				return -1
+		}
+		else{
+			if(a[key] < b[key])
+				return 1
+			else
+				return -1
+		}
+	}
+	array.sort(sortType);
+}
+
+sort(persons, "age"); 
+sort(persons, "name", false); 
+console.log(persons);
+``` 
+
+### array map
+
+```javascript
+var array1 = ["1", {}, null, undefined, "500", 700];
+var array2 = array1.map(function(arrayItem){
+	if(typeof(arrayItem) === "string")
+		return +arrayItem;
+	return arrayItem;
+});
+
+console.log(array2);
+```
+
+### array reduce
+
+```javascript
+var array = ["0", 5, 3, "string", null].reduce(function(previousValue, currentValue, index, array){
+	if(typeof(previousValue) !== "number" )
+		return currentValue;
+	else if(typeof(currentValue) !== "number")
+		return previousValue;
+	else 
+		return previousValue * currentValue;
+});
+
+console.log(array);
+```
+
+### object filter
+
+```javascript
+var phone = {
+    brand: "meizu",
+    model: "m2",
+    ram: 2,
+    color: "black",
+};
+
+function filter(object, validate){
+	var obj = {};
+	var keys = Object.keys(object);
+	for (var i = 0; i < keys.length; i++) {
+		if(validate(keys[i], object[keys[i]]))
+		obj[keys[i]] = object[keys[i]];
+	}
+	return obj;
+}
+
+var phone2 = filter(phone,function(key,value){
+    return (key == "color" || value == 2);
+});
+console.log(phone2);
+```
+
+### object map
+
+```javascript
+function map(obj, cond){
+	var keys = Object.keys(obj);
+	var newObject = {};
+	var resObject = {};
+	
+	for (var i = 0; i < keys.length; i++) {
+		newObject = cond(keys[i], obj[keys[i]])
+		var keys2 = Object.keys(newObject);
+		resObject[keys2[0]] = newObject[keys2[0]];
+	}
+	return resObject;
+}
+
+var result = map({name: "Иван", age: 17},function(key,value){
+    var result = {};
+    result[key+"_"] = value + "$";
+    return result;
+})
+
+console.log(result);
+```
+
+### Калькулятор
+
+```javascript
+var userVar = prompt("Введите выражение");
+
+console.log(userVar);
+function eval(userVariableInit){
+	var userVariable = [];
+	for (var i = 0; i < userVariableInit.length; i++) {
+		userVariable[i] = userVariableInit[i];
+	}
+	if(userVariable.indexOf("(") > -1)
+	{
+		var userVar = [];
+
+		do{
+			userVariable.splice(userVariable.indexOf("("), 2,eval(userVariable.splice(userVariable.indexOf("(") + 1, userVariable.indexOf(")") - userVariable.indexOf("(") - 1)));
+		}
+		while(userVariable.indexOf("(") > -1)
+		userVar = userVariable;
+	}
+	else 
+		var userVar = userVariable;
+
+	var array = [];
+	var bool = true;
+	for (var i = 0, p = 0, c = 0; i < userVar.length ; i++,p++) {
+		
+		
+		switch(userVar[i]){
+			case "+":
+				array.push("+");
+				bool = false;
+				break;
+			case "-":
+				array.push("-");
+				bool = false;
+				break;
+			case "*":
+				array.push("*");
+				bool = false;
+				break;
+			case "/":
+				array.push("/");
+				bool = false;
+				break;
+			default:
+				if(i != 0 && bool)
+				{
+					p--;
+					c++;
+					array[p] = userVar[i] + array[p];
+					bool = true;
+					
+				}
+				else
+				{
+
+					array[p] = userVar[i]
+					bool = true;
+				}
+		}
+		
+	}
+	var result = 0;
+	for (var i = 0; i < array.length; i++) {
+		if(!(i % 2))
+			array[i] = +array[i];
+	}
+	for (var i = 0; i < array.length; i++) {
+		if(i % 2){
+			
+			if(array[i] === "+"){
+				if(i === 1)
+					result += array[i - 1] + array[i + 1];
+				else 
+					result += array[i + 1];
+			}
+			if(array[i] === "-"){
+				if(i === 1)
+					result = array[i - 1] - array[i + 1];
+				else 
+					result -= array[i + 1];
+			}
+			if(array[i] === "*"){
+				if(i === 1)
+					result = array[i - 1] * array[i + 1];
+				else 
+					result *= array[i + 1];
+			}
+			if(array[i] === "/"){
+				if(i === 1)
+					result = array[i - 1] / array[i + 1];
+				else 
+					result /= array[i + 1];
+			}
+		}
+	}
+	console.log(array);
+	return result;
+	
+}
+var result = eval(userVar);
+
+console.log(result);
+```