JS-Intermediate-Course/063-function-constructor.js at main · FullStack-Flow/JS-Intermediate-Course · GitHub

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// 1: FUNCTIONS ARE OBJECTS
functionname(params){
return`Hello, ${params}`
}

console.log(name.params)// name
console.log(name.length)// 1

name.callCount=0;
name.version="1.0"

console.log(name.version)// 1.0

// 2: THE FUNCTION CONSTRUCTOR
// Traditional way
functionadd(a,b){
returna+b;
}

// Using Function constructor
constaddConstructor=newFunction('a','b','return a + b');

console.log(add(5,3));// 8
console.log(addConstructor(5,3));// 8

constx=10;

functionnormal(){
returnx;// Works - accesses outer scope
}

constconstructed=newFunction('return x');
// Error! Only has global scope


// 3: BUILT-IN FUNCTION PROPERTIES
functioncalculateTotal(){
return100;
}

console.log(calculateTotal.name);// "calculateTotal"

constmultiply=(a,b)=>a*b;
console.log(multiply.name);// "multiply"

functionlogCall(fn, ...args){
console.log(`Calling: ${fn.name}`);
returnfn(...args);
}

functionadd(a,b){
returna+b;
}
console.log(add.length);// 2

functionwithRest(a,b, ...rest){}
console.log(withRest.length);// 2 (rest params don't count)

functionwithDefault(a,b=5){}
console.log(withDefault.length);// 1 (stops at first default)

functionPerson(name){
this.name=name;
}

Person.prototype.greet=function(){
return`Hi, I'm ${this.name}`;
};

constalice=newPerson("Alice");
console.log(alice.greet());// "Hi, I'm Alice"

// 4: CUSTOM PROPERTIES & PRACTICAL USE
// Function Counter:
functiontrackCalls(){
trackCalls.count++;
console.log(`Called ${trackCalls.count} times`);
}

trackCalls.count=0;

trackCalls();// Called 1 times
trackCalls();// Called 2 times

// Memoization (Caching):
functionfibonacci(n){
if(n<=1)returnn;

if(fibonacci.cache[n]){
returnfibonacci.cache[n];
}

constresult=fibonacci(n-1)+fibonacci(n-2);
fibonacci.cache[n]=result;
returnresult;
}

fibonacci.cache={};

console.log(fibonacci(10));// 55
console.log(fibonacci(10));// 55 (cached!)
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// 1: FUNCTIONS ARE OBJECTS
functionname(params){
return`Hello, ${params}`
}

console.log(name.params)// name
console.log(name.length)// 1

name.callCount=0;
name.version="1.0"

console.log(name.version)// 1.0

// 2: THE FUNCTION CONSTRUCTOR
// Traditional way
functionadd(a,b){
returna+b;
}

// Using Function constructor
constaddConstructor=newFunction('a','b','return a + b');

console.log(add(5,3));// 8
console.log(addConstructor(5,3));// 8

constx=10;

functionnormal(){
returnx;// Works - accesses outer scope
}

constconstructed=newFunction('return x');
// Error! Only has global scope


// 3: BUILT-IN FUNCTION PROPERTIES
functioncalculateTotal(){
return100;
}

console.log(calculateTotal.name);// "calculateTotal"

constmultiply=(a,b)=>a*b;
console.log(multiply.name);// "multiply"

functionlogCall(fn, ...args){
console.log(`Calling: ${fn.name}`);
returnfn(...args);
}

functionadd(a,b){
returna+b;
}
console.log(add.length);// 2

functionwithRest(a,b, ...rest){}
console.log(withRest.length);// 2 (rest params don't count)

functionwithDefault(a,b=5){}
console.log(withDefault.length);// 1 (stops at first default)

functionPerson(name){
this.name=name;
}

Person.prototype.greet=function(){
return`Hi, I'm ${this.name}`;
};

constalice=newPerson("Alice");
console.log(alice.greet());// "Hi, I'm Alice"

// 4: CUSTOM PROPERTIES & PRACTICAL USE
// Function Counter:
functiontrackCalls(){
trackCalls.count++;
console.log(`Called ${trackCalls.count} times`);
}

trackCalls.count=0;

trackCalls();// Called 1 times
trackCalls();// Called 2 times

// Memoization (Caching):
functionfibonacci(n){
if(n<=1)returnn;

if(fibonacci.cache[n]){
returnfibonacci.cache[n];
}

constresult=fibonacci(n-1)+fibonacci(n-2);
fibonacci.cache[n]=result;
returnresult;
}

fibonacci.cache={};

console.log(fibonacci(10));// 55
console.log(fibonacci(10));// 55 (cached!)
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// 1: FUNCTIONS ARE OBJECTS
functionname(params){
return`Hello, ${params}`
}

console.log(name.params)// name
console.log(name.length)// 1

name.callCount=0;
name.version="1.0"

console.log(name.version)// 1.0

// 2: THE FUNCTION CONSTRUCTOR
// Traditional way
functionadd(a,b){
returna+b;
}

// Using Function constructor
constaddConstructor=newFunction('a','b','return a + b');

console.log(add(5,3));// 8
console.log(addConstructor(5,3));// 8

constx=10;

functionnormal(){
returnx;// Works - accesses outer scope
}

constconstructed=newFunction('return x');
// Error! Only has global scope


// 3: BUILT-IN FUNCTION PROPERTIES
functioncalculateTotal(){
return100;
}

console.log(calculateTotal.name);// "calculateTotal"

constmultiply=(a,b)=>a*b;
console.log(multiply.name);// "multiply"

functionlogCall(fn, ...args){
console.log(`Calling: ${fn.name}`);
returnfn(...args);
}

functionadd(a,b){
returna+b;
}
console.log(add.length);// 2

functionwithRest(a,b, ...rest){}
console.log(withRest.length);// 2 (rest params don't count)

functionwithDefault(a,b=5){}
console.log(withDefault.length);// 1 (stops at first default)

functionPerson(name){
this.name=name;
}

Person.prototype.greet=function(){
return`Hi, I'm ${this.name}`;
};

constalice=newPerson("Alice");
console.log(alice.greet());// "Hi, I'm Alice"

// 4: CUSTOM PROPERTIES & PRACTICAL USE
// Function Counter:
functiontrackCalls(){
trackCalls.count++;
console.log(`Called ${trackCalls.count} times`);
}

trackCalls.count=0;

trackCalls();// Called 1 times
trackCalls();// Called 2 times

// Memoization (Caching):
functionfibonacci(n){
if(n<=1)returnn;

if(fibonacci.cache[n]){
returnfibonacci.cache[n];
}

constresult=fibonacci(n-1)+fibonacci(n-2);
fibonacci.cache[n]=result;
returnresult;
}

fibonacci.cache={};

console.log(fibonacci(10));// 55
console.log(fibonacci(10));// 55 (cached!)
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// 1: FUNCTIONS ARE OBJECTS
functionname(params){
return`Hello, ${params}`
}

console.log(name.params)// name
console.log(name.length)// 1

name.callCount=0;
name.version="1.0"

console.log(name.version)// 1.0

// 2: THE FUNCTION CONSTRUCTOR
// Traditional way
functionadd(a,b){
returna+b;
}

// Using Function constructor
constaddConstructor=newFunction('a','b','return a + b');

console.log(add(5,3));// 8
console.log(addConstructor(5,3));// 8

constx=10;

functionnormal(){
returnx;// Works - accesses outer scope
}

constconstructed=newFunction('return x');
// Error! Only has global scope


// 3: BUILT-IN FUNCTION PROPERTIES
functioncalculateTotal(){
return100;
}

console.log(calculateTotal.name);// "calculateTotal"

constmultiply=(a,b)=>a*b;
console.log(multiply.name);// "multiply"

functionlogCall(fn, ...args){
console.log(`Calling: ${fn.name}`);
returnfn(...args);
}

functionadd(a,b){
returna+b;
}
console.log(add.length);// 2

functionwithRest(a,b, ...rest){}
console.log(withRest.length);// 2 (rest params don't count)

functionwithDefault(a,b=5){}
console.log(withDefault.length);// 1 (stops at first default)

functionPerson(name){
this.name=name;
}

Person.prototype.greet=function(){
return`Hi, I'm ${this.name}`;
};

constalice=newPerson("Alice");
console.log(alice.greet());// "Hi, I'm Alice"

// 4: CUSTOM PROPERTIES & PRACTICAL USE
// Function Counter:
functiontrackCalls(){
trackCalls.count++;
console.log(`Called ${trackCalls.count} times`);
}

trackCalls.count=0;

trackCalls();// Called 1 times
trackCalls();// Called 2 times

// Memoization (Caching):
functionfibonacci(n){
if(n<=1)returnn;

if(fibonacci.cache[n]){
returnfibonacci.cache[n];
}

constresult=fibonacci(n-1)+fibonacci(n-2);
fibonacci.cache[n]=result;
returnresult;
}

fibonacci.cache={};

console.log(fibonacci(10));// 55
console.log(fibonacci(10));// 55 (cached!)
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// 1: FUNCTIONS ARE OBJECTS
functionname(params){
return`Hello, ${params}`
}

console.log(name.params)// name
console.log(name.length)// 1

name.callCount=0;
name.version="1.0"

console.log(name.version)// 1.0

// 2: THE FUNCTION CONSTRUCTOR
// Traditional way
functionadd(a,b){
returna+b;
}

// Using Function constructor
constaddConstructor=newFunction('a','b','return a + b');

console.log(add(5,3));// 8
console.log(addConstructor(5,3));// 8

constx=10;

functionnormal(){
returnx;// Works - accesses outer scope
}

constconstructed=newFunction('return x');
// Error! Only has global scope


// 3: BUILT-IN FUNCTION PROPERTIES
functioncalculateTotal(){
return100;
}

console.log(calculateTotal.name);// "calculateTotal"

constmultiply=(a,b)=>a*b;
console.log(multiply.name);// "multiply"

functionlogCall(fn, ...args){
console.log(`Calling: ${fn.name}`);
returnfn(...args);
}

functionadd(a,b){
returna+b;
}
console.log(add.length);// 2

functionwithRest(a,b, ...rest){}
console.log(withRest.length);// 2 (rest params don't count)

functionwithDefault(a,b=5){}
console.log(withDefault.length);// 1 (stops at first default)

functionPerson(name){
this.name=name;
}

Person.prototype.greet=function(){
return`Hi, I'm ${this.name}`;
};

constalice=newPerson("Alice");
console.log(alice.greet());// "Hi, I'm Alice"

// 4: CUSTOM PROPERTIES & PRACTICAL USE
// Function Counter:
functiontrackCalls(){
trackCalls.count++;
console.log(`Called ${trackCalls.count} times`);
}

trackCalls.count=0;

trackCalls();// Called 1 times
trackCalls();// Called 2 times

// Memoization (Caching):
functionfibonacci(n){
if(n<=1)returnn;

if(fibonacci.cache[n]){
returnfibonacci.cache[n];
}

constresult=fibonacci(n-1)+fibonacci(n-2);
fibonacci.cache[n]=result;
returnresult;
}

fibonacci.cache={};

console.log(fibonacci(10));// 55
console.log(fibonacci(10));// 55 (cached!)
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// 1: FUNCTIONS ARE OBJECTS
functionname(params){
return`Hello, ${params}`
}

console.log(name.params)// name
console.log(name.length)// 1

name.callCount=0;
name.version="1.0"

console.log(name.version)// 1.0

// 2: THE FUNCTION CONSTRUCTOR
// Traditional way
functionadd(a,b){
returna+b;
}

// Using Function constructor
constaddConstructor=newFunction('a','b','return a + b');

console.log(add(5,3));// 8
console.log(addConstructor(5,3));// 8

constx=10;

functionnormal(){
returnx;// Works - accesses outer scope
}

constconstructed=newFunction('return x');
// Error! Only has global scope


// 3: BUILT-IN FUNCTION PROPERTIES
functioncalculateTotal(){
return100;
}

console.log(calculateTotal.name);// "calculateTotal"

constmultiply=(a,b)=>a*b;
console.log(multiply.name);// "multiply"

functionlogCall(fn, ...args){
console.log(`Calling: ${fn.name}`);
returnfn(...args);
}

functionadd(a,b){
returna+b;
}
console.log(add.length);// 2

functionwithRest(a,b, ...rest){}
console.log(withRest.length);// 2 (rest params don't count)

functionwithDefault(a,b=5){}
console.log(withDefault.length);// 1 (stops at first default)

functionPerson(name){
this.name=name;
}

Person.prototype.greet=function(){
return`Hi, I'm ${this.name}`;
};

constalice=newPerson("Alice");
console.log(alice.greet());// "Hi, I'm Alice"

// 4: CUSTOM PROPERTIES & PRACTICAL USE
// Function Counter:
functiontrackCalls(){
trackCalls.count++;
console.log(`Called ${trackCalls.count} times`);
}

trackCalls.count=0;

trackCalls();// Called 1 times
trackCalls();// Called 2 times

// Memoization (Caching):
functionfibonacci(n){
if(n<=1)returnn;

if(fibonacci.cache[n]){
returnfibonacci.cache[n];
}

constresult=fibonacci(n-1)+fibonacci(n-2);
fibonacci.cache[n]=result;
returnresult;
}

fibonacci.cache={};

console.log(fibonacci(10));// 55
console.log(fibonacci(10));// 55 (cached!)
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// 1: FUNCTIONS ARE OBJECTS
functionname(params){
return`Hello, ${params}`
}

console.log(name.params)// name
console.log(name.length)// 1

name.callCount=0;
name.version="1.0"

console.log(name.version)// 1.0

// 2: THE FUNCTION CONSTRUCTOR
// Traditional way
functionadd(a,b){
returna+b;
}

// Using Function constructor
constaddConstructor=newFunction('a','b','return a + b');

console.log(add(5,3));// 8
console.log(addConstructor(5,3));// 8

constx=10;

functionnormal(){
returnx;// Works - accesses outer scope
}

constconstructed=newFunction('return x');
// Error! Only has global scope


// 3: BUILT-IN FUNCTION PROPERTIES
functioncalculateTotal(){
return100;
}

console.log(calculateTotal.name);// "calculateTotal"

constmultiply=(a,b)=>a*b;
console.log(multiply.name);// "multiply"

functionlogCall(fn, ...args){
console.log(`Calling: ${fn.name}`);
returnfn(...args);
}

functionadd(a,b){
returna+b;
}
console.log(add.length);// 2

functionwithRest(a,b, ...rest){}
console.log(withRest.length);// 2 (rest params don't count)

functionwithDefault(a,b=5){}
console.log(withDefault.length);// 1 (stops at first default)

functionPerson(name){
this.name=name;
}

Person.prototype.greet=function(){
return`Hi, I'm ${this.name}`;
};

constalice=newPerson("Alice");
console.log(alice.greet());// "Hi, I'm Alice"

// 4: CUSTOM PROPERTIES & PRACTICAL USE
// Function Counter:
functiontrackCalls(){
trackCalls.count++;
console.log(`Called ${trackCalls.count} times`);
}

trackCalls.count=0;

trackCalls();// Called 1 times
trackCalls();// Called 2 times

// Memoization (Caching):
functionfibonacci(n){
if(n<=1)returnn;

if(fibonacci.cache[n]){
returnfibonacci.cache[n];
}

constresult=fibonacci(n-1)+fibonacci(n-2);
fibonacci.cache[n]=result;
returnresult;
}

fibonacci.cache={};

console.log(fibonacci(10));// 55
console.log(fibonacci(10));// 55 (cached!)
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// 1: FUNCTIONS ARE OBJECTS
functionname(params){
return`Hello, ${params}`
}

console.log(name.params)// name
console.log(name.length)// 1

name.callCount=0;
name.version="1.0"

console.log(name.version)// 1.0

// 2: THE FUNCTION CONSTRUCTOR
// Traditional way
functionadd(a,b){
returna+b;
}

// Using Function constructor
constaddConstructor=newFunction('a','b','return a + b');

console.log(add(5,3));// 8
console.log(addConstructor(5,3));// 8

constx=10;

functionnormal(){
returnx;// Works - accesses outer scope
}

constconstructed=newFunction('return x');
// Error! Only has global scope


// 3: BUILT-IN FUNCTION PROPERTIES
functioncalculateTotal(){
return100;
}

console.log(calculateTotal.name);// "calculateTotal"

constmultiply=(a,b)=>a*b;
console.log(multiply.name);// "multiply"

functionlogCall(fn, ...args){
console.log(`Calling: ${fn.name}`);
returnfn(...args);
}

functionadd(a,b){
returna+b;
}
console.log(add.length);// 2

functionwithRest(a,b, ...rest){}
console.log(withRest.length);// 2 (rest params don't count)

functionwithDefault(a,b=5){}
console.log(withDefault.length);// 1 (stops at first default)

functionPerson(name){
this.name=name;
}

Person.prototype.greet=function(){
return`Hi, I'm ${this.name}`;
};

constalice=newPerson("Alice");
console.log(alice.greet());// "Hi, I'm Alice"

// 4: CUSTOM PROPERTIES & PRACTICAL USE
// Function Counter:
functiontrackCalls(){
trackCalls.count++;
console.log(`Called ${trackCalls.count} times`);
}

trackCalls.count=0;

trackCalls();// Called 1 times
trackCalls();// Called 2 times

// Memoization (Caching):
functionfibonacci(n){
if(n<=1)returnn;

if(fibonacci.cache[n]){
returnfibonacci.cache[n];
}

constresult=fibonacci(n-1)+fibonacci(n-2);
fibonacci.cache[n]=result;
returnresult;
}

fibonacci.cache={};

console.log(fibonacci(10));// 55
console.log(fibonacci(10));// 55 (cached!)