EN
JavaScript - how to use '.apply(...)' method with (or instead) 'new' operator
4 points
In this article we would like to show how to create object with MyClass.apply(...) method instead of new operator in JavaScript.
Simple solution for modern JavaScript:
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const parameters = ['a', 'b'];2
const object = new MyClass(parameters);Simple solution for older JavaScript:
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function MyClass(a, b) {2
console.log(a + ' ' + b);3
this.print = function(c, d) {4
console.log(a + ' ' + b + ' -> ' + c + ' ' + d);5
};6
}7
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var object = { };9
MyClass.apply(object, ['a', 'b']);10
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object.print('c', 'd');Note: read this article to see
MyClass.call(...)method examples.
Check below alternative solutions:
There are few different ways how to achieve same effect, what was presenbted in this section.
In modern JavaScript, the following approach is mostly correct.
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class MyClass {2
constructor(a, b) {3
this.a = a;4
this.b = b;5
console.log(a + ' ' + b);6
}7
print(c, d) {8
console.log(this.a + ' ' + this.b + ' -> ' + c + ' ' + d);9
}10
}11
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const parameters = ['a', 'b'];13
const object = new MyClass(parameters);14
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object.print('c', 'd');xxxxxxxxxx1
function MyClass(a, b) {2
console.log(a + ' ' + b);3
this.print = function(c, d) {4
console.log(a + ' ' + b + ' -> ' + c + ' ' + d);5
};6
}7
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var object = new (MyClass.bind.apply(MyClass, [null, 'a', 'b']));9
object.print('c', 'd');xxxxxxxxxx1
function MyClass(a, b) {2
console.log(a + ' ' + b);3
this.print = function(c, d) {4
console.log(a + ' ' + b + ' -> ' + c + ' ' + d);5
};6
}7
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var object = new (Function.prototype.bind.apply(MyClass, [null, 'a', 'b']));9
object.print('c', 'd');