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While designing a definition file, I came across this error (TS2507).
How can I specify a type to be a 'constructor function type' ?
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We tried to instantiate a value that is not a constructor as a constructor, which caused the error. To solve the "TypeError: 'X' is not a constructor" in JavaScript, make sure to only use the new operator on valid constructors, e.g. classes or constructor functions.
The JavaScript exception "is not a constructor" occurs when there was an attempt to use an object or a variable as a constructor, but that object or variable is not a constructor.
Javascript has provided some built-in constructors. Those built-in functions include object(), string(), number, etc. We cannot include Math object in those built-in constructors because Math is a global object. The 'new' keyword cannot be used with Math.
A constructor is a special function that creates and initializes an object instance of a class. In JavaScript, a constructor gets called when an object is created using the new keyword. The purpose of a constructor is to create a new object and set values for any existing object properties.
If you are defining an interface, you can declare that it is a constructor like such:
interface SomeInterface {
new(someParam: any): SomeInterface
}
This is useful when you are defining typings for already existing JS libraries. See this SO answer for more details.
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