org.sonar.l10n.javascript.rules.javascript.S2999.html Maven / Gradle / Ivy
Why is this an issue?
JavaScript has the new keyword that is used in conjunction with constructor functions to create new instances of objects. When you use
the new keyword with a function, it signifies that the function is intended to be used as a constructor function to create objects.
Any function can be used as a constructor function by convention. Constructor functions are used to create new objects with the same structure or
properties. They are typically named with an initial capital letter to distinguish them from regular functions.
To create a new instance of an object using the constructor function, you use the new keyword before the function call.
The new keyword should only be used with objects that define a constructor function. Attempting to use it with an object or a variable
that is not a constructor will raise a TypeError.
function MyClass() {
this.foo = 'bar';
}
const someClass = 1;
const obj1 = new someClass; // Noncompliant: someClass is a variable
const obj2 = new MyClass(); // Noncompliant if parameter considerJSDoc is true. Compliant when considerJSDoc is false
Always use the new keyword with constructor functions or classes.
/**
* @constructor
*/
function MyClass() {
this.foo = 'bar';
}
const someClass = function(){
this.prop = 1;
}
const obj1 = new someClass;
const obj2 = new MyClass();
Resources
Documentation
- MDN web docs -
new operator
- MDN web docs - Constructor
- MDN web docs -
TypeError: "x" is not
a constructor