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Kaziu
Kaziu

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"😭 Escape from crazy boy friend!" explain Dependency Injection simplest way

#javascript #beginners #programming

🔥 Dangerous situation

Woman has crazy boy friend, but she can't escape from him. She doesn't have other choice.

class Woman { makeLover(){ const bf = new CrazyMan() bf.stayWith() } } class CrazyMan { stayWith() { console.log('I am dangerous man, stay with me') } } const woman = new Woman() woman.makeLover() // I am dangerous man, stay with me
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👦 There is good man !!

create GoodMan class

class Woman { makeLover(){ const bf = new CrazyMan() bf.stayWith() } } class CrazyMan { stayWith() { console.log('I am dangerous man, stay with me') } } // good man !!!!!!! class GoodMan { stayWith() { console.log('I am good man, stay with me') } } const woman = new Woman() woman.makeLover() // 😰 But still she stays with dangerous man // "I am dangerous man, stay with me"
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Why she still stays with dangerous man ??
because she (Woman class) depends on dangerous man

class Woman { makeLover(){ // here, crazy man exists in Woman class, he is aaaaaaalways with her const bf = new CrazyMan() bf.stayWith() } }
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So help her !! What should we do ???

class Woman { // She does not depend on crazy man, she has choice now !! constructor(man) { this.man = man } makeLover(){ this.man.stayWith() } } class CrazyMan { stayWith() { console.log('I am dangerous man, stay with me') } } class GoodMan { stayWith() { console.log('I am good man, stay with me') } } const man = new GoodMan() const woman = new Woman(man) woman.makeLover() // I am good man, stay with me
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We could help her by erasing dependency on crazy man 😀

This is simplest way to explain, from now you could easily get other articles about Dependency Injection😎

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