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javascriptobjecttypescripttypescript1.8

TypeScript hasOwnProperty equivalent

In JavaScript, if I want to loop through a dictionary and set properties of another dictionary, I'd use something like this:

for (let key in dict) {
  if (obj.hasOwnProperty(key)) {
    obj[key] = dict[key];
  }
}

If obj is a TypeScript object (instance of a class), is there a way to perform the same operation?

Solution

  • If obj is a TypeScript object (instance of a class), is there a way to perform the same operation?

    Your JavaScript is valid TypeScript (more). So you can use the same code as it is.

    Here is an example:

    class Foo{
    foo = 123
}

const dict = new Foo();
const obj = {} as Foo;

for (let key in dict) {
  if (obj.hasOwnProperty(key)) {
    obj[key] = dict[key];
  }
}

    Note: I would recommend Object.keys(obj).forEach(k=> even for JavaScript, but that is not the question you are asking here.